Bulletin of the American Physical Society
APS March Meeting 2022
Volume 67, Number 3
Monday–Friday, March 14–18, 2022; Chicago
Session T00: Poster Session III (1pm 4pm CST)Poster Undergrad Friendly

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Room: McCormick Place Exhibit Hall F1 

T00.00001: SEMICONDUCTORS, INSULATORS, AND DIELECTRICS


T00.00002: Crystal anisotropy in topological spin Hall effect in 2D materials with an ideal skyrmion gas Andrei S Zadorozhnyi The Hall effect depending on conduction electron spin projection becomes very different for anisotropic 2D crystals. In this case the spindependent electron current strongly determined by the orientation angle, θ, of the sample with respect to an applied electric field. The spinup and down components of the direct and Hall charge currents oscillate with the angle 2θ. The direct and Hall components of the current have the structure where there are the angleindependent part, oscillation amplitude, and phase shift. All three quantitates strongly depend on the electron spin projection, electron mass ratio, and skyrmion size. We find that there are "magic" orientation angles where the spinup, spindown, and total Hall currents vanish. There is a great interest in computations based on 2D materials with skyrmions. Such properties can be useful for computer logic operations based on skyrmions. 

T00.00003: Turning graphene into nodalline semimetals by vacancy engineering Wei Chen, Matheus de Sousa, Fujun Liu, Mariana Malard, Fanyao Qu We elaborate that singlelayer graphene can be turned into a nodalline or nodalloop semimetal by introducing periodic vacancies, opening the possibility of fabricating graphenebased electronic or spintronic devices with novel functionalities. The principle is that by removing carbon atoms such that the lattice becomes nonsymmorphic, every two sublattices in the unit cell will map to each other under glide plane operation. This mapping yields degenerate eigenvalues for the glideplane operation, which guarantees that the energy bands must stick together pairwise at a boundary of the Brillouin zone. Moving away from the Brillouin zone boundary causes the symmetryenforced nodal lines to split, resulting in accidental nodal lines caused by the crossings of the split bands. Moreover, the vacancyengineered graphene has a dramatically enlarged density of states at the Fermi level. This mechanism is applicable to a variety of crystalline structures, irrespective of the details of the systems, and valid even in the presence of strong spinorbit coupling. 

T00.00004: Vanishing of anomalous quantum Hall and quantum spin Hall phase in band deformed insulators. SAYAN MONDAL, Saurabh Basu We look for distinct topological phases of a two dimensional honeycomb lattice, one in which the time reversal symmetry (TRS) is violated, and in another it is preserved. In these systems, the vanishing of the topological phases can be induced via a band deformation that may be caused by varying the nearest neighbour hopping parameters. In particular, among the neighbouring sites, one may continuously vary one of them (say, t_{1}), while keeping the other two hopping terms (say, t) fixed. For the TRS broken case, where there is a topological gap in the system caused by complex second neighbour hopping (Haldane model), the gap vanishes at t_{1}=2t, the so called semiDirac limit. As t_{1} becomes larger than 2t, a gap reopens in the spectrum, which however can be shown to be a trivial gap and the system behaves like a band insulator. We study such a topological phase transition via the disappearance of the anomalous Hall conductivity and the Chern number. In the TRS invariant case, which can be considered as two copies of the Haldane model, one for each spin, there occurs a similar vanishing of the quantum spin Hall phase that can be captured through vanishing of the topological invariant (the Ζ_{2} invariant) in the semiDirac limit, beyond which the system demonstrates dispersion same as that of a trivial insulator. Summarizing, we show that a band deformation in a honeycomb lattice is capable of inducing a phase transition irrespective of whether TRS is broken or preserved. 

T00.00005: Raman Mapping Analysis of Graphene Transferred by Multiple Techniques Anthony Trofe, Kirby b Schmidt, Sajedeh Pourianejad, Olubunmi Ayodele, Tetyana Ignatova Graphene transfer utilizing polymer assisted transfer technique leaves impurities. These impurities affect both electrical and structural properties of graphene. Determining the quality of the sample is important for use in later device applications. Extracting full width half maximum (FWHM), center location, and intensity of Raman peaks offers insight into how a sample has been changed from the transfer process. Using a free Python package and easily accessible libraries it is possible to extract and visualize the properties of graphene samples. By analyzing Raman data, we have optimized the polymer assisted graphene transfer utilizing various polymers and a process for cleaning the sample using a Soxhlet apparatus. 

T00.00006: The Quantum Pinch Effect in Magnetized Semiconducting Quantum Wires Manvir S Kushwaha We investigate a twocomponent, cylindrical, quasionedimensional quantum plasma subjected to a {\em radial} confining harmonic potential and an applied magnetic field in the symmetric gauge. It is demonstrated that such a system as can be realized in semiconducting quantum wires offers an excellent medium for observing the quantum pinch effect at low temperatures. An exact analytical solution of the problem allows us to make significant observations: surprisingly, in contrast to the classical pinch effect, the particle density as well as the current density display a {\em determinable} maximum before attaining a minimum at the surface of the quantum wire. The effect will persist as long as the equilibrium pair density is sustained. Therefore, the technological promise that emerges is the route to the precise electronic devices that will control the particle beams at the nanoscale. 

T00.00007: Topological insulator and artificial crystals for Hydroelastic waves Marc Fermigier, Antonin Eddi, Federigo Ceraudo The Quantum Hall effect is the first example of the new topological phases of matter, the state responsible for such effect does not break any symmetries and its explanation comes from topology. The topological phases with nonzero Chern number can lead to interesting wave transport properties such as unidirectional edge propagation immune to backscattering and robustness against defects/disorder. The study of topological phases has been applied to a variety of classical physical systems, such as photonic [1,2], sonic cristals [3–6] and water waves systems [7,8], each of them presents different challenges to break the time reversal symmetry (T symmetry). Focusing on water wave system it's not trivial to break the T symmetry, in fact rotational water flows are needed comporting a large amount of energy. Another approach to face this experimental challenge is to mimic the Quantum Spin Hall Effect realizing a topological insulator (TI) [9,10], in this case the T symmetry is preserved. We propose to study topological phases using a new approach based on hydroelastic waves using the spatial symmetry of the unit cell of a triangular lattice in order to construct a pseudoT symmetry and pseudospindependent TI. A band inversion can be achieved by adjusting the lattice's parameters. 

T00.00008: Resonant coulomb energy transfer in transition metal dichalcogenide moirés Aidan P Reddy, Allan H MacDonald We report on a theoretical study of Coulombmediated energy transfer between electrically isolated transition metal dichalcogenide (TMD) moirés. We discuss two distinct models (approximations) intended to be accurate when the intermoiré Coulomb interaction is either strong or weak compared to the moiré bandwidth. In the former case, which occurs when the intermoiré spacing d is smaller than the moiré lattice constant a_{M} and the twist angle θ≤2º, intermoiré energy transfer arises from interactions between nearby pairs of artificial moleculessites of the moiré lattice where lowenergy moiré band states localize. In the latter case, which occurs when θ≥2º, we describe the energy transfer with a Fermi's golden expression rule based on the random phase approximation for intermoiré twoparticle scattering amplitudes. Due to a competition between moiré lattice site densities and bandwidths, the energy transfer rate is maximized at twist angles θ≈4º, at which an interfacial thermal conductance G on the order of 100 MW/(m^{2}K) is achievable. We relate our models of the strong and weak coupling regimes to models of the analogous regimes in photosynthetic, intermolecular energy transfer. 

T00.00009: Investigation on the nanostructure of Nafion ultrathin film at Pt and carbon catalyst layer of PEMFC Seung Geol Lee, Haisu Kang In this study, hydrated Nafion film in the catalyst layer of the cathode for a polymer electrolyte membrane fuel cell is investigated using the molecular dynamics simulation method, exhibiting different structural characteristics on Pt and carbon surfaces. Water molecules, hydronium ions, and sulfonate groups are highly concentrated at the interfacial region between the Nafion phase and the Pt surface, whereas Nafion backbone chains are highly concentrated at the interface between the Nafion phase and the carbon surface. Pair correlation function analysis revealed that the water molecules and sulfonate groups in the hydrated Nafion phase are more associated with the Pt surface compared to the carbon surface due to their strong, attractive interactions with the Pt surface that makes the dimension of the hydrated Nafion phase 4–7% thinner on the Pt surface. Moreover, wateroccupied volume analysis suggested that water molecules on the carbon surface can form a largesize water phase between the Nafion phase and the carbon surface because the Nafion–carbon interface is not tightly integrated due to their weak interaction. Related to these structural characteristics, the water diffusion and proton vehicular diffusion are suppressed in the interfacial region of the Pt surface due to the highly packed structures in the water phase as well as the polymer phase, in addition to the strong molecular interaction with the Pt surface, whereas the proton hopping diffusion is enhanced due to the welldeveloped organized water phase through the hydrogen bonding network. 

T00.00010: Alldielectric double split ring metasurface for structural colour generation Keshav Samrat Modi, Satya Pratap Singh, Umesh Tiwari, Ravindra Kumar Sinha The metasurfaces are attractive artificially structured materials in the Nanophotonics domain. The metaldielectric metasurfaces are promising but experience high losses in optical wavelengths. This drawback is overcome by the use of alldielectric metasurfaces (ADMS). The specifically designed ADMS based on double split silicon (Si) ring can produce the sharp Fanoresonance characterised by the asymmetric line shape. The Mie resonance in high index Si dielectric produces high Qfactor resonance. Such types of ADMS based Fanoresonances are capable of providing refractive index sensors with high figure of merit and optical modulators with broadband tunability. In this work, we show that the above ADMS producing Fanoresonance can be utilized to achieve structural colours where Fanoresonance with small linewidth and sharp peaks generate highly pure and saturate colour gamut. By scaling the feature size of metasurface, we are able to produce Fano resonance in reflectance profile with peak position at 360 nm, 541 nm and 720 nm, which corresponds to colours in visible spectrum, respectively. The linewidth of Fanoresonance for structural colour is in range of 8 to 17 nm. Such structures can be used in pixels of nextgeneration reflective colour displays. 

T00.00011: Tan's contact for bosonic systems with a fixed chemical potential Bilal Tanatar, Abdulla Rakhimov, Tolib Abdurakhmonov The temperature dependence of Tan’s contact parameter C and its derivatives for spin gapped 

T00.00012: Photoinduced phase transition and associated time scales in the excitonic insulator Ta2NiSe5 Tanusree Saha, Denis Golež, Giovanni De Ninno, Jernej Mravlje, Yuta Murakami, Barbara Ressel, Matija Stupar, Primož Rebernic Ribič We investigate the nonequilibrium electronic structure and characteristic timescales in a candidate excitonic insulator, Ta2NiSe5, using time and angleresolved photoemission spectroscopy. Following a strong photoexcitation, the band gap closes transiently within 100 fs, i.e., on a timescale faster than the typical lattice vibrational period. Furthermore, we find that the characteristic time associated with the rise of the photoemission intensity above the Fermi level decreases with increasing excitation strength, while the relaxation time of the electron population towards equilibrium shows an opposite behavior. We argue that these experimental observations can be consistently explained by an excitonic origin of the band gap in the material. The excitonic picture is supported by microscopic calculations based on the nonequilibrium Green's function formalism for an interacting twoband system. We interpret the speedup of the rise time with fluence in terms of an enhanced scattering probability between photoexcited electrons and excitons, leading to an initially faster decay of the order parameter and the inclusion of electronphonon coupling at a semiclassical level changes only the quantitative aspects of the proposed dynamics, while the qualitative features remain the same. 

T00.00013: Characterization of Sn/CuO interface by xray photoelectron spectroscopy Allen Hillegas, Anil R Chourasia The Sn/CuO interface has been investigated by the techniques of xray photoelectron spectroscopy and atomic force microscopy. Thin films of tin were deposited on CuO at room temperature by ebeam method. The thickness of the tin film was varied between 3 Å and 10 Å. The tin 3d, oxygen 1s, and copper 2p regions were recorded by XPS. The spectral data show the absence of the high binding energy satellite in the copper 2p regions. This corresponds to the reduction of CuO to elemental copper. The tin overlayer is observed to get oxidized to SnO_{2}. The thickness of oxidized tin was found to depend upon the initial thickness of the tin overlayer. The reaction is observed to continue until the tin overlayer exceeds a thickness of 7 Å. Beyond this thickness unreacted tin is observed. The AFM study shows nonuniformity of the SnO_{2} film on copper. The study provides a means of preparing SnO_{2} of nanodimensions. 

T00.00014: Characterization of Thicknesses of MultiLayered Thin Films Based on Recursive Calculations of Refraction at Layers' Interfaces Ahmed Elrashidy, JiaAn Yan Since the discovery of Graphene in 2004, a variety of methods have been developed to determine the thickness of thin films of twodimensional atomic crystals. Optical methods are noninvasive, highly accurate, costefficient, and can be used to determine the thickness of large samples. Here, we apply a numerical method based on recursive calculations of the reflectance over a range of incident angles as determined by the numerical aperture in multilayered thin films to calculate the optical contrast. We show that the calculated optical contrast can be used to characterize the thickness of the thin films. Our results agree with other work in the literature. 

T00.00015: Observation of phase synchronization and alignment during free induction decay of quantum spins with Heisenberg interactions Juergen Schnack Equilibration of observables in closed quantum systems that are described by a unitary time evolution is a meanwhile 

T00.00016: Spectroscopic Signatures of Interlayer Coupling in Janus MoSSe/MoS_{2} Heterostructures Kunyan Zhang, Yunfan Guo, Daniel T Larson, Ziyan Zhu, Shiang Fang, Efthimios Kaxiras, Jing Kong, Shengxi Huang Engineering interlayer coupling through the twist angle or applied electric field has gained interest due to the breakthroughs of magicangle graphene and twisted transition metal dichalcogenides (TMDs). The structural asymmetry of Janus TMD, in which the chalcogens are different on both sides, provides an inherent vertical electric field to tune the interlayer coupling. Here, we demonstrate the manipulation of phononic and excitonic properties of Janus MoSSe/MoS_{2} heterostructures through changing the twist angle or reversing the electric field direction by forming S/S and Se/S interfaces. The MoSSe/MoS_{2} heterostructure with the S/S interface displays higher interlayer phonon mode frequencies and stronger PL quenching of the intralayer exciton, suggesting a stronger interlayer coupling than the Se/S interface. Firstprinciples calculations support the experiments and explain the interlayer coupling by the charge density redistribution and band hybridization. Our work paves the way for tailoring van der Waals interactions using Janus TMDs, which can facilitate the design of Moiré superlattices. 

T00.00017: Growth of highquality biofriendly ZnO:Ga thin films by pulsed laser deposition technique Anya Tiwari, Gia Mishra, Anand Sharma Zinc oxide (ZnO) is a versatile material that exhibits a variety of interesting properties, including a wide electronic band gap, high exciton binding energy, and biocompatibility. Due to this unique combination of properties, it finds application in a vast range of areas, spanning from ultraviolet lasers to transparent semiconductors and from transparent magnets to sunscreens. ZnO can also be used to form selfcleaning surfaces that can kill harmful pathogens with exposure to sunlight. In order to create these selfcleaning surfaces, a thin coating of the material must be prepared on the surface. In this study, we report the growth of Gallium (Ga) doped ZnO films on sapphire. To grow these films, we used a pulsed laser deposition technique. In this technique, ultrahigh power laser pulses from an excimer laser were made incident on a solid ZnO:Ga target. This led to the ablation of the target material resulting in the formation of a plasma plume which got deposited on the sapphire substrate that was kept at a 5 cm distance from the target. The temperature of the sapphire substrate was varied from 100 C to 700 C. Films were characterized using several different techniques and a correlation was established between deposition parameters and the properties of the films. 

T00.00018: Mesoscopic Difference of Hydrogen Double Minimum Well in Proton Irradiated Ferroelectric System SeHun Kim We investigate the microscopic structure of hydrogen doublewell potentials in a hydrogenbonded ferroelectric system exposed to radioactive particles of 

T00.00019: Abnormal Surface Nonlinear Optical Responses in Topological Materials Haowei Xu Nonlinear optical (NLO) responses of topological materials are under active research in recent years. Yet by far, most studies focused on the bulk properties, whereas the surface effects and the difference between surface and bulk responses have not been systematically studied. Here we develop a generic Green’s function framework to investigate the surface NLO properties of topological materials. The Green’s function framework can naturally incorporate manybody effects and can be easily extended to highorder NLO responses. Using T_{d}WTe_{2 }as an example, we reveal that the surface can behave disparately from the bulk under light illumination. Remarkably, the shift and circular currents on the surface can flow in opposite directions to those in the bulk interior. Moreover, the lightinduced spin current on the surface can be orders of magnitude stronger than its bulk counterpart. We also study the responses under inhomogeneous field and higherorder NLO effect, which are all distinct on the surface. These anomalous surface NLO responses suggest that light can be a valuable tool for probing the surface states of topological materials. On the other hand, the surface effects shall be prudently considered when investigating the optical properties of topological materials, especially if the material is of nanoscale and/or the light penetration depth is small. 

T00.00020: Crossover between Majorana and Andreev bound states in Majorana nanowires, and the fate of the topological phase transition Angela Nigro, Pasquale Marra Majorana bound states (MBS) are topologically protected and spatiallyseparated zeroenergy excitations localized at the opposite ends of Majorana nanowires, i.e., proximitized semiconducting nanowires with strong spinorbit coupling and broken timereversal symmetry, and exhibit nonabelian exchange statistics that may lead to a major breakthrough in the field of faulttolerant quantum computation. Quite a few experiments observed signatures compatible with the existence of MBS in Majorana nanowires. However, these signatures may also be explained by the presence of trivial Andreev bound states (ABS) with zero or nearzero energies, induced by random disorder, impurities, or smooth confinement. In general, trivial ABS can be described as a pair of partiallyseparated Majorana modes, as opposed to the fullyseparated MBS. In our work, we study the continuous crossover interpolating between fullyseparated MBS, partiallyseparated ABS, and fullylocalized ABS. We will characterize this crossover in terms of the global and local topological invariants, fermion parity, Majorana polarization, and density of states. We found that the topological phase transition between trivial ABS and nontrivial MBS does not correspond to the closing of the bulk gap, but to a simple parity crossing of the ABS from trivial to nontrivial regime. This result does not contradict the bulkedge correspondence: Indeed, the field inhomogeneities driving the Majorana/Andreev crossover have a length scale comparable with the nanowire length, and therefore correspond to a nonlocal perturbation which breaks the topological protection of the MBS. 

T00.00021: Describing holedoped Mott insulators through spinonholon bound state excitations Shashank Anand, Matthias Punk, Erica W Carlson The introduction of holes in a Mott insulator induces novel quantum states of matter. The low holedensity regime, characterized by strong competition between kinetic and interaction energies of the electrons, is still not well understood. We study the tJ model within the slave boson formalism in order to obtain an effective meanfield description of low holedoped Mott insulators. Under the assumption that there are spinonholon boundstates, this becomes the quantum dimer model, which has been used by Punk et al., [PNAS, 2015] to describe the pseudogap phase of the cuprate superconductors. We obtain the phase diagram of such a system and calculate the threepoint spinspinhole correlations. 

T00.00022: Thickness film effect on charge transport in nanostructure indeno[1, 2b]fluorene6,12 dione Riad S Masharfe Indenofluorene compounds have been applied as organic fieldeffect transistors. Indeno[1,2b]flourene6,12dione (IFdione) films of different film thickness have been obtained using a thermal evaporating technique. The XRD analysis revealed that the crystalline nature of the IFdione films with thickness beyond 150 nm had been boosted by increasing the film thickness. The increase of the film thickness from 150 nm to 540 nm led to a rise in the mean crystallite size values from 11.65 to 19.16 nm. The variation of the electrical conductivity of IFdione thin films with the reciprocal temperatures showed that the thermal activation energy of the sample had been diminished as the film thickness increases. Mott's hopping of variable range conduction operation explained the behavior of the conductivity. The study of the currentdensityvoltage (JV) characteristics of IFdione thinfilm confirmed that the Ohmic conduction mechanism is dominant below a threshold voltage (V_{t}), whereas the space charge limited conduction has been satisfied beyond V_{t}. It was found that the total trap concentration values are compatible with the other organic molecules. Also, many electrical parameters have been evaluated for different film thicknesses. 

T00.00023: Radiation characteristics of a finitelength electric dipole in hyperbolic materials Muhammad Faryad, Aamir Hayat The hyperbolic materials exist naturally and can also be fabricated artificially as an assembly of electrically thin parallel sheets or wires. These materials have an axis of symmetry and two permittitivity scalars to characterize the response of electric field in the directions along the symmetry axis and perpendicular to the symmetry axis. However, one of the permittivity scalar has a negative real part while the other a positive real part giving rise to hyperbolic dispersion curve. To understand the radiation characteristics of finitesized elementary sources, we have derived the expressions of radiation by finitelength electric dipole in hyperbolic materials. The analytical results and radiation patterns are presented. 

T00.00024: Critical properties of the prethermal Floquet Time Crystal Aditi Mitra The critical properties characterizing the formation of the Floquet time crystal in the prethermal phase are investigated analytically in the periodically driven O(N) model. In particular, we focus on the critical line separating the trivial phase with period synchronized dynamics and absence of longrange spatial order from the nontrivial phase where longrange spatial order is accompanied by perioddoubling dynamics. In the vicinity of the critical line, with a combination of dimensional expansion and exact solution for N→∞, we determine the exponent ν that characterizes the divergence of the spatial correlation length of the equaltime correlation functions, the exponent β characterizing the growth of the amplitude of the orderparameter, as well as the initialslip exponent θ of the aging dynamics when a quench is performed from deep in the trivial phase to the critical line. The exponents ν,β,θ are found to be identical to those in the absence of the drive. In addition, the functional form of the aging is found to depend on whether the system is probed at times that are small or large compared to the drive period. The spatial structure of the twopoint correlation functions, obtained as a linear response to a perturbing potential in the vicinity of the critical line, is found to show algebraic decays that are longer ranged than in the absence of a drive, and besides being perioddoubled, are also found to oscillate in space at the wavevector ω/(2v), v being the velocity of the quasiparticles, and ω being the drive frequency. 

T00.00025: Electron capture and emission dynamics of selfassembled quantum dots far from equilibrium with the environment Thomas Heinzel, Laurin Schnorr, Andreas D Wieck, Arne Ludwig The electron transfer dynamics between selfassembled quantum dots and their environment are measured under nonequilibrium conditions by timedependent capacitance spectroscopy. The quantum dots are embedded in a wide spacer, which inhibits elastic tunneling to or from the reservoirs. At certain bias voltages, electron capture and emission are both significant. A rate equation model is used to determine the corresponding transfer rates and the average occupation numbers of the dots as a function of the bias voltage. 

T00.00026: Growth and optimization of structural properties of (110)oriented YBa_{2}Cu_{3}O_{7} (YBCO) / PrBa_{2}(Cu_{0.8}Ga_{0.2})_{3}O_{7} (PBCGO) heterostructure Julia A Jones, Hom Kandel, Chang Beom Eom, Yuchuan Yao, Nathan Arndt, Li Zhongrui, Jungwoo Lee Epitaxial growth and characterization of heterostructures made of hightemperature superconductor YBCO and cuprate insulator PBCGO are critical for developing many superconductor electronic devices including Josephson junctions, threeterminal devices, multichip modules, and other circuit applications. Of particular interest is the Josephson junction device with applications ranging from magnetometer sensors, quantum computing, radio telescopes, and national defense. These heterostructures are also important for fundamental science research, such as studies of mechanisms for highTC and 2D superconductivity, and measurement of correlation energy. 

T00.00027: Seebeck domain formed by grain boundaries of 1HMoS_{2} Seungil Baek, HoKi Lyeo, Jun Jung, Euicheol Shin, YongHyun Kim 1HMoS_{2} is a highly renowned candidate for nextgeneration electronic devices due to its intrinsic band gap, but its growth is easily materialized to a polycrystalline structure. Understanding the properties of this dislocation is essential not only in enabling largescale growth but also in a way that it opens a possibility of utilizing a defect itself. Here, by the ab initio based scanning Seebeck microscope (SSM) simulation, we demonstrate that peculiar Seebeck domain of opposite sign is formed around the grain boundaries of 1HMoS_{2}. The intrinsic dipole field and the localized defect states inside the band gap play a predominant role in determining the sign of the domain. 

T00.00028: Polariton based optical switching devices in TMDC's: A comparative analysis between Ψshaped and Yshaped channel guides for switching device optimization. Patrick Serafin Using the Langevin equation, we numerically model the stochastic diffusive dynamics of a dipolariton gas in an optical microcavity with a MoSe_{2}WS_{2 }TMDC bilayer. The dipolariton particles, which are a three way mixture of direct exciton, indirect exciton and photon, are considered to be confined in a Ψshaped channel guide (with and without a buffer branch) as well as a Yshaped channel guide. By variance of channel parameters such as electric field angle and electric driving force, we are able to study the resulting dipolariton branch redistributions. We are able to attain performances of >90% in both channel geometries for particular channel parameters, whilst making comparative analyses between the two varying channel geometries. Our results open the route towards the development of room temperature based optical switching devices for various channel guide geometries. 

T00.00029: Fixedpoint structure and critical behavior of generalized GrossNeveu models in 2+1 dimensions Konstantinos Ladovrechis, Shouryya Ray, Tobias P Meng, Lukas Janssen The universal behavior of matter near points of continuous phase transitions is an intriguing phenomenon in condensed matter and statistical physics. At quantum critical points, the presence of gapless fermion degrees of freedom leads to new quantum universality classes without any classical analogues. Here, we discuss zerotemperature phase transitions between twodimensional Dirac semimetals and longrangeordered phases, in which spin and/or charge symmetries are spontaneously broken. These transitions are described by generalized GrossNeveu models in 2+1 dimensions. We identify and classify fixed points of the renormalization group in the theory space spanned by a basis of shortrange interactions compatible with the given symmetries, and we compute the corresponding quantum critical behaviors. Implications for the physics of interacting Dirac systems will be discussed as well. 

T00.00030: Suppression of Heating due to Emergence of Local Conservation Laws in Clean Interacting Floquet Quantum Matter Asmi Haldar We consider a clean quantum system subject to strong periodic driving. The existence of a dominant energy scale, h^{x}_{D}, can generate considerable structure in an effective description of a system that, in the absence of the drive, is nonintegrable and interacting, and does not host localization. In particular, we uncover a threshold of drive strength beyond which the system transits sharply from a quantum chaotic to a dynamically frozen regime. We identify special points of freezing in the space of drive parameters (frequency and amplitude). At those points, the dynamics is severely constrained due to the emergence of an almost exact, local conserved quantity, which scars the entire Floquet spectrum by preventing the system from heating up ergodically, starting from any generic state, even though it delocalizes over an appropriate subspace. At large drive frequencies, where a naïve Magnus expansion would predict a vanishing effective (average) drive, we devise instead a strongdrive Magnus expansion in a moving frame. There, the emergent conservation law is reflected in the appearance of the “integrability” of an effective Hamiltonian. These results hold for a wide variety of Hamiltonians, including the Ising model in a transverse field in any dimension and for any form of Ising interaction. The phenomenon is also shown to be robust in the presence of twobody Heisenberg interactions with any arbitrary choice of couplings. Furthermore, we construct a realtime perturbation theory that captures resonance phenomena where the conservation breaks down, giving way to unbounded heating. This approach opens a window on the lowfrequency regime where the Magnus expansion fails. 

T00.00031: Ultrafast Optical Control of Magnetic Order and Fermi Surface Topology at a Quantum Critical Point Benedikt Fauseweh, JianXin Zhu Designing material properties on demand has important implications to future technological applications. Although it is theoretically possible to tune various intrinsic competing interactions, there are fundamental limitations to this approach for quantum materials at equilibrium. In recent years, ultrafast spectroscopy has evolved as a promising tool to use light to dynamically induce nontrivial electronic states of matter. Here we investigate light pulse driven dynamics in a heavy fermion system close to quantum criticality. We show, with a minimal Kondo lattice model, that light can dehybridize the local Kondo screening and induce magnetic order out of a previously paramagnetic state. Depending on the laser pulse field parameters, it is possible to deconfine the Kondo singlet and thereby induce second order phase transition to a dynamically ordered state, as well as a dynamical Lifshitz transition that changes the Fermi surface topology from hole to electronlike. We also calculate a few experimental measurable quantities for verification. 

T00.00032: Geometric Response and DisclinationInduced Skin Effects in NonHermitian Systems Penghao Zhu We study the geometric response of threedimensional nonHermitian crystalline systems with nontrivial pointgap topology. For systems with fourfold rotation symmetry, we show that in the presence of disclination lines with a total Frank angle, which is an integer multiple of 2π, there can be nontrivial onedimensional pointgap topology along the direction of the disclination lines. This results in disclinationinduced nonHermitian skin effects. By doubling a nonHermitian Hamiltonian to a Hermitian threedimensional chiral topological insulator, we show that the disclinationinduced skin modes are zero modes of the effective surface Dirac fermion(s) in the presence of a pseudomagnetic flux induced by disclinations. Furthermore, we find that our results have a field theoretic description, and the corresponding geometric response actions (e.g., the Euclidean WenZee action) enrich the topological field theory of nonHermitian systems. 

T00.00033: DefectCapture Dynamics and Effect on Electron Transport Danhong Huang Using a quantumstatistical theory, we study defect dynamics, including capture and relaxation rates as functions of temperature and doping density. By utilizing these results, defect energyrelaxation, capture and escape rates are numerically evaluated. Meanwhile, we also calculate the energy and momentumrelaxation rates as well as the current suppression factor. By combining these results, the temperature dependence for longitudinal & Hall mobility in single and multiquantum wells is obtained. Additionally, we compute the defect correction to polarization and dielectric functions, and apply them to acquire the first two moment equations from a general Boltzmann transport theory. Furthermore, the inverse momentumrelaxation time and mobility tensor are derived analytically with the help of defectcorrected polarization function. 

T00.00034: Quasi2D surface behavior of aged βFeSe single crystals Lucio Lanoël In this work we report on the βFeSe system and its dependence with aging. On freshly samples two vibrational modes attributed to A_{1g }(Se) and B_{1g }(Fe) are observed on its Raman spectra. After tens of days in ambient conditions, a new peak appears. We propose that this new peak is due to a loss of symmetry in the first sheets of the system, which occurs with aging, that make this new peak Raman active. This hypothesis is supported by Group theory calculations which predicts three optical modes near the center of the Brillouin zone, one attributed to Se, other to Fe and the last one a combination of both kind of atoms, all Raman active in the new symmetry group. Also we measured an enhancement of the critical temperature of the system in a sample with an aged face. βFeSe films are known to have higher critical temperature than bulk single crystals. 

T00.00035: A heat bath approach to anomalous thermal transport: interplay of Berry curvature and inelastic dissipation Zhiqiang Wang, Kathryn Levin We present results for the entire set of anomalous charge and heat transport coefficients for metallic systems in the presence of finite temperature. In realistic physical systems 

T00.00036: Growth and Characterization of Thin Films of Zinc Oxide and Related Materials for Application in Micatronics Gitanjali Mishra, Anya Tiwari, Ashutosh Tiwari Mica offers a wide variety of applications due to its superior electrical and thermal properties. This includes high dielectric strength, low heat loss, flexibility, and excellent electrical insulation. Recently, Mica has attracted tremendous attention because of its application in Micatronics, a new paradigm of flexible electronics. Numerous substrate materials, such as dielectric polymers, have been utilized in past for realizing flexible electronic devices, however, they function at low operating temperatures. There is a high demand for flexible, durable, and environmentally friendly electronic devices that can operate under ambient conditions. Micatronics fulfills these demands. In this study, we report the growth and characterization of thin films of Zinc Oxide and related materials on Mica for application in flexible Micatronic devices. Films were prepared by a pulsed laser deposition technique where a solid pellet of the constituent material was ablated by using highpower KrF excimer laser pulses. The high power of the laser pulses causes the stoichiometric ablation of the target material thereby creating a plasma plume that gets deposited on the Mica substrate. Films thus prepared were thoroughly characterized using XRD, SEM, EDX, and Raman spectroscopy. 

T00.00037: Magnetic field effect on the lasing behavior of GaAs nanowires on iron Gyanan Aman, Martin Fränzl, Mykhaylo Lysevych, Hark Hoe Tan, Chennupati Jagadish, Heidrun Schmitzer, Marc Cahay, Hans Peter Wagner We investigated the effect of a magnetic field on the lasing behavior of GaAs nanowires (NWs) on an iron film. The conical GaAs NWs with an acceptor concentration of 2 x 10^{19 }cm^{3} were coated with an 8 nm thick Al_{2}O_{3} layer to reduce band bending. The NWs on iron film were excited with ultrashort 150 fs pulses from Ti: Sapphire laser tuned to 720 nm at a cryostat temperature of 77 K. A permanent magnet was integrated into the cryostat system allowing to apply a magnetic field of ~0.3 T in Faraday and Voigt configuration with respect to the long axis of the NWs. Scanning microscope images reveal average dimensions of the lasing NWs to be ~ 3.3 μm long with a tip diameter of ~ 370 nm and a base diameter of ~ 530 nm. The NWs show an onset of lasing at ~40 mW without magnet field. Finitedifference timedomain simulations show that a predominantly photonic mode with moderate plasmonic losses of ~ 3000 cm^{1}, is responsible for lasing. While the lasing behavior was not noticeably influenced by a magnetic field in Faraday configuration the threshold power was significantly increased in Voigt configuration. The reduced NW laser intensity in Voigt configuration suggests a magnetic field induced spatial charge separation of the eh pairs. 

T00.00038: Electronic and mechanical properties of subnm diameter carbon nanotubes Heran Yang The electronic and mechanical properties of carbon nanotubes such as high Young's modulus and strength, high surface to volume ratio, and high electrical conductivity make them ideal for a wide range of uses from biomedicine to electronic devices. These properties are known to be diameterdependent, but the diameterdependency at subnanometer diameters and the mechanistic basis for the dependency is less well understood. In our work, using density function theory (DFT) simulations, we find that carbon nanotubes have two distinct bond lengths, with the nonuniformity in bond length being significant for subnm diameter nanotubes and affecting their properties. In this poster, we present the effects for both defective and non defective zigzag carbon nanotubes. We discuss the diameter dependent band gap and the electronic basis of the anomaly in theoretical predictions of bandgap size for (m,0) chirality nanotubes for m<7. We also present the diameterdependence of Young's modulus, strength, and toughness for subnm diameter carbon nanotubes. For carbon nanotubes with monovacancy defect, we find that JahnTeller reconstruction does not occur due to high curvature of the nanotube, which is different from graphene. The electronic consequence for these findings will also be discussed. 

T00.00039: Photoinduced charge flow of graphebased field effect device Byeoungju Lee, Eunjip Choi, Kwangnam Yu, Jiho Kim Graphenebased field effect transistor(GFET) exhibits a large photoinduced current change. This effect is utilized for photo detector applications. However the underlying mechanism for the current change is not solidly established. Here we fabricated GOS(graphene/oxide/pSi) field effect device and measured I_{DS} and I_{GS} currents while manipulating the light. Upon turning on the light, a shortlived current I_{GS} flow is observed in concurrence with permanent I_{DS} jump. 

T00.00040: Chiral phonons in honeycomb sublattice of layered CoSlike compounds Andrzej Ptok, Aksel Kobiałka, Malgorzata Sternik, Jan Lazewski, Pawel T Jochym, Andrzej M Oles, Svetoslav Stankov, Przemyslaw Piekarz Hexagonal and kagome lattices exhibit extraordinary electronic properties. It is a natural consequence of additional discrete degree of freedom associated with a valley or the occurence of electronic flatbands. Combination of both types of lattices, observed in CoSnlike compounds, leads not only to the topological electronic behavior, but also to the emergence of chiral phonon modes. Here, we study CoSnlike compounds in the context of realization of chiral phonons. Previous theoretical studies demonstrated that the chiral phonons can be found in ideal twodimensional hexagonal or kagome lattices. However, it turns out that in the case of CoSnlike systems, the kagome lattice formed by dblock element is decorated by the additional pblock atom. This results in a two dimensional triangular lattice of atoms with nonequal masses and the absence of chiral phonons in the kagome plane. Contrary to this, the interlayer hexagonal lattice of pblock atoms is preserved and allows for the realization of chiral phonons. We discuss properties of these chiral phonons in seven CoSnlike compounds and demonstrate that they do not depend on atomic mass ratio or the presence of intrinsic magnetic order. The chiral phonons of dblock atoms can be restored by removing the inversion symmetry. 

T00.00041: AntiPoiseuille Flow: Increased Vortex Velocity at Superconductor Edges Takuya Okugawa, Avishai Benyamini, Andrew J Millis, Dante M Kennes Using the timedependent Ginzburg Landau equations we study driven vortex motion in two dimensional superconductors in the presence of a physical boundary. We observe that when current is uniformly sourced from one and drained from the other side of a finite torus geometry, vortices start to move perpendicular to the direction of the current flow due to the applied Lorentz force, as expected. At smaller sourced currents the lattice moves as a whole. At larger sourced current, due to the local suppression of the superconducting order parameter in the vortex cores, vortices prefer to move in separated channels. Since superconductivity is weakened at the edges of the sample, within each channel vortices will flow faster at the edges of the sample compared to the bulk. Thus, the vortex flow is opposite to the behaviour of Poiseuille's flow. Furthermore, we uncover a stickslip motion of the vortex lattice as the sourced current is increased and vortices in the channel at the boundary break free from the Abrikosov lattice, accelerate, move past their neighbors and then slow down as another Abrikosov lattice is reestablished. So vortices in the boundary channel stick to the Abrikosov lattice then slip and then stick again at which point the stickslip process starts over. 

T00.00042: Intrinsic defects and perturbation of charge density waves (CDW) in 1TTiSe_{2} Imrankhan B Mulani Charge density wave is an exciting quantum phenomenon. 1TTiSe_{2}, a layered transition metal dichalcogenide (TMDC), undergoes a phase transition to a commensurate 2X2 CDW state below T_{CDW } ∽ 200 K. Excitonic condensation, JahnTeller mechanism, or both are contested mechanisms behind the secondorder CDW phase transition in 1TTiSe_{2. }Intrinsic defects like intercalation, substitution, or vacancies, introduced while growing the crystals, can be used to probe the nature of CDWs. We used scanning tunneling microscopy (STM) to study CDWs in the presence of Ti intercalation defect sites. STM images are used to measure the correlation length of CDWs. We observed a reduction in the correlation length of CDWs as Ti intercalation concentration increases. Ti intercalant causes the formation of small CDWregions separated by domain boundaries. The electropositive nature of Ti intercalant leads to a change in carrier concentration, coloumb screening of electons and holes, affecting exciton condensate. This indicates that the excitonic condensation is the mechanism of the formation of the CDW state in 1TTiSe_{2. } 

T00.00043: μSR study of evolution of timereversal symmetry in the superconducting state of dilute Nd substitution in Pr_{1x}Nd_{x}Os_{4}Sb_{12} PeiChun Ho, Douglas E MacLaughlin, M Brian Maple, Lei Shu, Adrian D Hillier, Oscar O Bernal, Tatsuya Yanagisawa, Pabitra K Biswas, Jian Zhang, Cheng Tan The Prrich end of the alloy series Pr_{1}_{−x}Nd_{x}Os_{4}Sb_{12} has been studied using muon spin rotation and relaxation. The end compound PrOs_{4}Sb_{12} is an unconventional heavyfermion superconductor, which exhibits a spontaneous magnetic field in the superconducting phase associated with broken timereversal symmetry (TRS). However, with a very low concentration of Nd (x ≥ 0.05), no such spontaneous field is observed, indicating that TRS has been recovered. The superfluid density determined from the vortexlattice field distribution is insensitive to Nd concentration for x ≤ 0.2. No Nd^{3+} static magnetism, ordered or disordered, is found down to the lowest temperatures of measurement. 

T00.00044: Electronic structure of superconducting nickelates probed by resonant photoemission spectroscopy Zhuoyu Chen, Motoki Osada, Danfeng Li, Emily M Been, Sudi Chen, Makoto Hashimoto, Donghui Lu, SungKwan Mo, Kyuho Lee, Bai Yang Wang, Fanny Rodolakis, Jessica L McChesney, Chunjing Jia, Brian Moritz, Thomas P Devereaux, Harold Y Hwang, ZhiXun Shen The discovery of infinitelayer nickelate superconductors has spurred enormous interest. While the Ni^{1+} cations possess nominally the same 3d^{9} configuration as Cu^{2+} in highT_{C} cuprates, the electronic structure consistencies and variances remain elusive, due to the lack of direct experimental probes. Here, we present a soft xray photoemission spectroscopy study on both parent and doped infinitelayer Prnickelate thin films with a doped perovskite reference. By identifying the Ni character with resonant photoemission and comparison to density function theory + U calculations, we estimate U ~ 5 eV, smaller than the charge transfer energy △ ~ 8 eV, in contrast to the cuprates being charge transfer insulators. Near the Fermi level, we observe a signature of rareearth spectral intensity in the parent compound, which is depleted upon doping. Our results demonstrate a complex interplay between the strongly correlated Ni 3d and the weaklyinteracting rareearth 5d states for the superconductivity in the nickelates. 

T00.00045: WentzelKramersBrillouin (WKB) semiclassical equations for alphaT_3 materials Andrii Iurov, Kathy Blaise, Chinedu Ejiogu, Liubov Zhemchuzhna, Godfrey A Gumbs, Danhong Huang We have derived WentzelKramersBrillouin (WKB) semiclassical equations for the pseudospin1 Dirac Hamiltonian for arbitrary α − T_{3} materials with hopping parameters 0 < α < 1. We have both derived the analytical expression for the semiclassical states and the transport equations connecting different orders of the hbarexpansion of the sought wave function. Our obtained results have several crucial applications. These include approximate evaluation of electron transmission and reflection over a nonsquare potential barrier with a nonlinear potential profile. 

T00.00046: Effect of defects covalent bonding in the optical absorption and electronic structure of carbon nanotubes Rafael R Del Grande, Rodrigo B Capaz, Marcos Menezes Singlewall carbon nanotubes (SWCNTs) are 1D materials that show great potential for technological applications. Previous theoretical and experimental studies show that sp^{3}defects introduce local modifications to the electronic structure, creating new photoluminescent states with redshifted energies. This effect is related to an exciton localization at the sp^{3} defects. Those functionalized SWCNTs show higher quantum efficiency and are promising candidates for single photon emitters. 

T00.00047: Higherorder topological superconductivity in doped topological insulators Julian P Ingham Higherorder topological superconductors are topological states protected by spatial symmetries that exhibit gapless modes at the corners/edges of 2d/3d samples. While these phases of matter have recently attracted immense theoretical interest, experimental candidates remain scarce. This talk describes a mechanism for superconductivity in doped topological insulators which intrinsically leads to a higher order topological phase. The mechanism is effective in materials with localized orbitals, and requires a minimum doping beyond which superconductivity ensues, providing useful criteria in the search for material realizations. Mapping out the phase diagram of the KaneMele model with Hubbardlike interactions, we find that past a critical doping, manybody effects give rise to two possible higherorder topological states, p+iτp and s_{τ}, the latter of which is partially protected from disorder by a generalized Anderson theorem. Symmetrybased indicator arguments and exact diagonalization results are presented which demonstrate the resulting higher order topology. As a demonstration of the theory, microscopic modelling is presented for an artificial topological insulator based on a semiconductor heterostructure; we find that the superconducting mechanism can be enhanced by varying the depth of the quantum well. 

T00.00048: Superconductivity in electrochemical exfoliated NbSe_{2} atomic layers Jinpei Zhao Monolayer NbSe_{2 }with noncentrosymmetric lattice exhibit unconventional Ising superconductivity where the spin of electrons is locked along outofplane direction by spinorbital interaction, which drives intense research interest. However, it is challenging to use mechanical exfoliation to fabricate a van der Waals heterostructure with monolayer due to the low yield percentage of largesized monolayers and environmental oxidation. Herein, we use a mild electrochemical exfoliation method to fabricate NbSe_{2} devices achieving high yield of largesized singlecrystal monolayers with high stability. In the asfabricated twisted NbSe_{2} devices, we observed that the critical current shows oscillating behavior with the magnetic field. It is reminiscent of the effect of a magnetic field on a frustrated Josephson junction array with triangular symmetry, which is realized in the twisted devices with moiré pattern. 

T00.00049: Evidence of singlets in a 122type Febased superconductor Ram Prakash Pandeya, Anup Pradhan Sakhya, Sawani Datta, Tanusree Saha, Giovanni De Ninno, Rajib Mondal, C. Schlueter, Andrei Gloskovskii, Paolo Moras, Matteo Jugovac, Carlo Carbone, A. Thamizhavel, Kalobaran Maiti Cuprate superconductors often show signature of ZhangRice singlet states in their photoemission spectral functions which are believed to play a role in their ground state properties. Here, we studied the core level spectra of a Febased superconductor, CaFe_{1.9}Co_{0.1}As_{2} (T_{c} = 15 K) in the 122family employing highresolution hard xray photoemission spectroscopy (HAXPES). While the As core level spectra show negligible change with doping and/or temperature, the Ca 2p HAXPES data show a decrease in surfacebulk difference with Codoping compared to its parent compound, CaFe_{2}As_{2}. The peak position shifts gradually towards lower binding energies with cooling. Interestingly, the Fe 2p spectra show emergence of a new feature at a lower binding energy relative to the screened Fe 2p peak in the doped sample. The intensity of this feature enhances with the decrease in temperature. The property of this feature is very similar to the ZhangRice singlets observed in cuprates and the low energy screened feature in manganites. Emergence of this feature in the superconducting composition and its enhancement with the decrease in temperature suggests relevance of the underlying interactions in the ground state properties of these Febased superconductors. 

T00.00050: Graphene confined in layered silicate Barbara Pacakova, Marian Matejdes, Paulo Henrique O Michels Brito, Steinar Raaen, Daniel Wagner, Leander Michels, Josef Breu, Jon Otto Fossum The real use of graphene in electronic devices, such as fieldeffect transistors (FET), meets several principal complications. Opening of graphene band gap usually leads to significant drop of electron mobility; graphenebased devices can be prevented from switching into the OFF state. Some of the complications can be overcome by nontrivial combining of graphene with insulating layers in 2D heterostructures, that allow for fabrication of a graphenebased FET with the high ON and OFF switching ratio^{1}. 

T00.00051: Large band gap of insulator clay nanosheets Barbara Pacakova, Per E Vullum, Jon Otto Fossum Two dimensional materials possess many unique properties. From the electronic structural point of view, one can find conductive, semiconducting and insulating single nanosheets. Here we report a wide band gap insulator (band gap energy up to 7.18.2 eV) nanosheets obtained by delamination of synthetic fluorohectorite clay testifying these nanosheets to be one of the largest band gap insulators in the world. The band gap has been determined by electron energy loss spectroscopy in a high resolution transmission electron microscope. Fluorohectorite clay 1 nm thick single nanosheets can be synthetized with highaspect ratio and lateral dimensions up to dozens of microns. This property renders the synthetic fluorohectorite nanosheets promising candidates for practical applications in electronic devices, serving as insulating nanosheets for deposition of graphene and various (semi)conductive 2D materials by selfassembly. 

T00.00052: Quantum thermodynamics and laser cooling with Silicon vacancies in diamond Paul Eastham, Conor Murphy Conventional optical refrigeration methods induce antiStokes fluorescence by weakly driving an optical transition at resonance. The emitted photons are higher in energy than those absorbed from the pumping laser, with the energy difference accounted for by the absorption of phonons from the host medium. We propose an alternative method for laser cooling which uses strong coherent driving, and analyse this method in the case of the Silicon vacancy defect center in diamond. The protocol exploits the formation of laser dressed states, which we show leads to an increase in the cooling power and reduced sensitivity to pump wavelength, when compared with the conventional weak incoherent driving method. We use a BornMarkov master equation to solve for the steady state of the driven open system and use the method of full counting statistics to compute the cooling spectrum. Our results suggest this approach could be effective for laser cooling to temperatures on the order of 1K. The protocol is not specific to the Silicon vacancy center, and sheds light on the role of coherence in laser cooling and in quantum thermal machines more generally. 

T00.00053: Advanced physical properties of natural vermiculite clay Barbara Pacakova, Jon Otto Fossum Vermiculite, layered ionic material, belongs to the family of layered silicates. It is very difficult to exfoliate vermiculite into the single sheets, compared to other layered clays with low surface charge, as the surface charge of vermiculite is too high, reaching values between 0.7 – 1. 

T00.00054: Superconductivity at ferromagnetic domain walls in hybrid InAs/EuS/Al nanowires. Part 2: studied by magnetotransport Juan Carlos Estrada Saldaña, Nabhanila Nandi, Alexandros Vekris, Michelle Turley, Irene P Zhang, Yu Liu, Mario Castro, Martin Bjergfelt, Sabbir A Khan, Sebastian Allende, Peter Krogstrup, Kathryn Moler, Kasper GroveRasmussen, Jesper Nygård The effect of magnetism on superconductivity shows dramatically in ferromagnet/superconductor bilayers. Magnetic domains in the ferromagnet destroy Cooper pairs in the superconductor, while domain walls preserve them [1]. As the spin of the surviving Cooper pairs is expected to depend on the underlying magnetic texture, the integration of the bilayer films with semiconductors can serve as basis for novel devices such as spintriplet Josephson junctions. 

T00.00055: FirstPrinciples Investigation of the Electronic Properties of 2D OrganicTMDC Heterostructures Edward Black, Edward Black, Juliana M Morbec Twodimensional transition metal dichalcogenides (TMDCs) are considered encouraging materials for photovoltaic applications, with differing electronic and optical properties from their bulk counterparts. Pentacene is an organic compound with high exciton mobility, and complimentary electronic properties to TMDCs. Here are investigated systems of adsorbed pentacene on to monolayers of GroupVI dichalcogenides; MoS2, MoSe2, WS2 and WSe2, for photovoltaic applications. Using ab initio methods within density functional theory, optimized atomic positions were calculated and energetically favourable adsorption sites of pentacene were determined. These sites were further investigated with a varying concentration of adsorbed pentacene, with the aim of investigating how moleculemolecule interactions affect the interaction between molecule and substrate. The electronic properties of the favourable systems were then probed and the charge balance of the systems analysed. 

T00.00056: Metasurfacebased broadband terahertz polarization converters JiHun Kang, Seojoo Lee, SangHun Lee, Minah Seo A phase modulating device, such as a phase retarder, allows conversion of the polarization state of electromagnetic waves and is at the core of various disciplines of optics including optical chemistry, bio optics, and optical engineering. In the terahertz spectral range, however, due to the lack of natural substances possessing strong birefringence, metasurfaces have been adapted to obtain desired polarization states in this region. The idea of employing metasurfaces mainly relies on the artificial designing of birefringence in the metasurfaces and the utilization of resonant light interaction with unit resonators. In particular, the latter allows the emergence of asufficient phase retardation in the transmitted light for the polarization conversion, but simultaneously it limits the operating spectral range to the proximity of the resonance frequencies of metasurfaces. 

T00.00057: Atomically sharp edges revealed in a selffolded graphene nanostructure Sunghyun Kim, Xiaoqin (Elaine) Li, Suenne Kim The crystallographic orientation of the edges of graphene nanostructures is of particular interest as it can strongly affect the electronic, optical, or magnetic properties of the nanostructures. Here, we produced a folded graphene nanostructure by drawing lines on a mechanically exfoliated graphene monolayer while applying a moderate normal force of about 10 nN using an atomic force microscope (AFM) tip[1]. Drawing a line in this way induced selffolding in the graphene monolayer. We acquired several lateral force microscopy (LFM) friction images based on the nanoscale stickslip phenomenon to investigate the crystallographic orientation of the exfoliated graphene edges and that of the selffolded graphene nanostructure edges. We found that there is a particularly favored crystallographic orientation in the selffolding process, and we will compare our results with previous studies investigating the edges of graphene folded using different methods. 

T00.00058: Spinorbit torque effect on magnetic defects in the surface of the topological insulator Bi_{2}Te_{3} Philipp Ruessmann, Adamantia Kosma, Stefan Blügel, Phivos Mavropoulos This work comprises a theoretical and computational investigation of the phenomenon of the spinorbit torque [1] in topological insulators. In particular, we present the spinorbit torque exerted on the magnetic moments of transitionmetal impurities (Cr, Mn, Fe, and Co) that are embedded in the surface of the topological insulator Bi_{2}Te_{3}, in response to an electrical current in the surface [2]. The scattering properties of surface states off multiple magnetic impurities are studied by firstprinciples calculations within the fullpotential relativistic KorringaKohnRostoker (KKR) Green function method [3]. The spinorbit torque calculations are carried out combining the KKR method with the semiclassical Boltzmann transport equation. We discuss the correlation of the spinorbit torque to spin current on the Fermi surface, analyzing the spin flux contribution to the spinorbit torque on defects. The effect of resonant scattering is discussed, interpreting the results of different defects systems. In addition, we relate the torque to the resistivity and the Joule heat production in these systems. Finally, we find that the special characteristics of the studied system, i.e., the metallic surface states and the perpendicular spinpolarization of the surface electrons with respect to the magnetization of defects, reinforce the spinorbit torque effect. Consequently, these systems are favorable materials for spintronic applications. We also predict that the Mn/Bi_{2}Te_{3} is the most promising among the studied systems for application of the spinorbit torque effect. 

T00.00059: Electrically Controlled Thermal Radiation from Reduced Graphene Oxide Membranes zhaolong chen We demonstrate a fabrication procedure of hybrid devices that consist of reduced graphene oxide films supported by porous polymer membranes that host ionic solutions. We find that we can control the thermal radiation from the surface of reduced graphene oxide through a process of electrically driven reversible ionic intercalation. Through a comparative analysis of the structural, chemical, and optical properties of our reduced graphene oxide films, we identify that the dominant mechanism leading to the intercalationinduced reduction of light emission is Pauli blocking of the interband recombination of charge carriers. We inspect the capabilities of our devices to act as a platform for the electrical control of midinfrared photonics by observing a biasinduced reduction of apparent temperature of hot surfacesvisualized through an infrared thermal camera. 

T00.00060: Superconductivity in hydrated Li_{x}(H_{2}O)_{y}TaS_{2} Huanlong Liu, Andreas J Schilling We have systematically studied the superconductivity in hydrated Li_{x}(H_{2}O)_{0.86}TaS_{2} solid solution which is prepared for different lithium contents. The powder Xray diffraction (PXRD) patterns suggest that all the samples are singlephase compounds, and the crystal structure is similar to that of 2HTaS_{2} (P6_{3}/mmc). Our transport measurements show a metallic behavior in the normal state and a transition to superconductivity at low temperatures for all involved Li_{x}(H_{2}O)_{0.86}TaS_{2 }samples. The superconducting transition temperature shows a domelike dependence on the lithium intercalation content, with a maximum T_{c} of 4.6 K for x ≈ 0.42. Both the specific heat and the large superconducting shielding fraction reveal the bulk nature of superconductivity. The parameters extracted from specificheat data are consistent with the T_{c} dependence on lithium content and suggest that superconductivity of hydrated Li_{x}(H_{2}O)_{0.86}TaS_{2 }is related to phonon softening and electron doping. 

T00.00061: Gaussian trajectory description of fragmentation in an isolated spinor condensate Lennart Fernandes, Michiel Wouters, Jacques Tempere Spin1 Bose gases quenched to spin degeneracy exhibit fragmentation: the appearance of a condensate in more than one singleparticle state. Due to its highly entangled nature, this collective state is beyond the scope of a Gaussian variational approximation of the manybody wave function. Here, we improve the performance of the Gaussian variational Ansatz by considering dissipation into a fictitious environment, effectively suppressing entanglement within individual quantum trajectories at the expense of introducing a classical mixture of states. We find that this quantum trajectory approach captures the dynamical formation of a fragmented condensate, and analyze how much dissipation should be added to the experiment in order to keep a single realization in a nonfragmented state. 

T00.00062: Order Fractionalization in a KitaevKondo model I: Introduction to the model. Piers Coleman and Alexei Tsvelik Piers Coleman The phenomenon of fractionalization, in which excitations breakup into 

T00.00063: Tunneling current and conductance of optically tunable Dirac particles with elliptical dispersion Paula Fekete, Andrii Iurov, Liubov Zhemchuzhna, Godfrey A Gumbs, Danhong Huang, Farhana Anwar, Dipendra Dahal, Nicholas Weekes Based on earlierobtained electron transmission, we have calculated the tunneling conductance and the current over a square potential barrier for both graphene and an αT3 lattice under a linearly polarized offresonant dressing field. The tunneling current is calculated using the transmission coefficient. Applying a dressing field with linear polarization leads to an anisotropy in the electron energy dispersion. Consequently, the circular cross section of the Dirac cone becomes elliptical. The major axis of this ellipse is not necessarily aligned with the direction of electron headon collisions with the potential barrier. This misalignment leads to asymmetric Klein tunneling. We demonstrate that the tunneling conductance exhibits unexpected properties due to the longitudinal component of the electron group velocity not being equivalent to the longitudinal momentum. 

T00.00064: MoGe Josephson junctions Ivan P Nevirkovets, Mikhail Belogolovskii, John B Ketterson We have fabricated and characterized MoGe/Al/AlO_{x}/(Al)MoGe Josephson junctions (JJs) using amorphous MoGe thin films with superconducting transition temperatures up to 7 K. Amorphous MoGe films are known to have very smooth and uniform surfaces, which allows us to achieve high quality tunnel barriers and excellent uniformity of the junction properties when using a very thin Al overlayer to form the barrier. Our experimental results and comparisons with the theoretical calculations confirm these behaviors. High uniformity of the characteristics of the MoGe junctions, which exceeds that of Nb/Al/AlO_{x}/(Al)/Nb junctions fabricated using the same equipment, is important for practical applications involving superconducting electronics. In particular, we suggest that MoGe junctions are especially suitable for applications where vertical stacking of multiple JJs is desirable, e.g., in voltage standards and Josephson oscillators. Exploiting these junctions in qubits is also expected. 

T00.00065: Extracting Wilson loops and fractional statistics from a ground state wave function on a disk ZePei Cian, Mohammad Hafezi, Maissam Barkeshli An essential aspect of topological phases of matter is the existence of Wilson loop operators which keep the ground state subspace invariant. Here we present and implement an unbiased numerical optimization scheme to systematically find the Wilson loop operators given a single ground state wave function of a gapped, translationally invariant Hamiltonian on a disk. We then show how these Wilson loop operators can be cut and glued through further optimization to give operators that can create, move, and annihilate anyon excitations. We then use these operators to determine the braiding statistics and topological twists of the anyons, yielding a way to fully extract topological order from a single wave function. We apply our method to the ground state of the perturbed toric code and doubled semion models with a Zeeman field that is up to a third of the critical value. From a contemporary perspective, this can be thought of as a machine learning approach to discover emergent 1form symmetries of a ground state wave function. 

T00.00066: Thermoelectric properties of inversion symmetry broken Weyl semimetalSuperconductor hybrid junction Ruchi Saxena, Nirnoy Basak, Pritam Chatterjee, Sumathi Rao, Arijit Saha Due to its nontrivial topology, Weyl semimetals (WSMs) exhibit many interesting physical effects such as the quantum anomalous Hall effect, the chiral magnetic effect, negativemagnetoresistance and unusual surface states called Fermi arcs. Intense theoretical and experimental research work have been carried out in both timereversal and inversion symmetry broken WSMs. Although electronic properties of WSMs (both in bulk and heterojunctions) have been extensively studied, there is less information available about its thermoelectric properties in hybrid setups. In particular, we are interested in studying thethermoelectric properties of heterostructures consisting of WSMs with superconductors which form the foundation of applications in electronics and spintronics. In this work, we theoretically investigate the thermoelectric properties of a junction consisting of an inversion symmetry broken WSM proximitized to a bulk swave superconductor (WSMSC junction), employing the BlonderTinkhamKlapwijk formulation for noninteracting electrons. Our study unfolds interesting features for various relevant physical quantities such as the thermal conductance, the thermoelectric coefficient and the figure ofmerit. We also explore the effects of an interfacial insulating (I) barrier (WSMISC junction) on thermoelectric response in the thin barrier limit. Furthermore, we compute the ratio of the thermal to the electrical conductance in different temperature regimes and find that theWiedemannFranz law is violated for small temperatures near the Weyl points while it saturates to the Lorentz number, away from the Weyl points, at all temperatures irrespective of the barrier strength. We compare and contrast this behaviour with other Dirac material heterostructures. Our study can facilitate the fabrication of mesoscopic thermoelectric devices based on WSMs. 

T00.00067: Polarizability, plasmons, and screening in TMoS2 with tilted Dirac bands Godfrey A Gumbs, Andrii Iurov In the presence of an external vertical electric field, it is evident that T MoS2 exhibits tilted Dirac bands which are valleyspinpolarized. Additionally, this material experiences a topological phase change between a topological insulator and band insulator for a critical value of the electric field. Using linear response theory, we calculate yhe polarization function which is in turn used to obtain the dielectric function. This latter quantity is then used to calculate the plasmon dispersion relation and impurity screening corresponding to tilted Dirac bands in both undoped and doped T MoS2 and the role played by varying the strength of the vertical electric field, the spinorbit coupling gap, and band tilting. 

T00.00068: Topological properties of multilayer magnon insulators Stephen Hofer, Trinanjan Datta, Dipanjan Mazumdar The potential for topological excitations in 2D magnetic insulators has proven to be an exciting field in recent years. In a recently published work it was shown that rhombohedrally stacked, ferromagnetically coupled multilayers with alternating DzyaloshinksiiMoriya interactions can host a multitude of topological phases[1]. These topological phases are characterized by their unique Chern numbers and sharp jumps in the thermal Hall conductance between phases. Motivated by experimental results, we extend the analysis of topological signatures in antiferromagnetically coupled and monoclinically stacked few layer 2D magnets. We report significant differences in the topological features between the rhombohedral and monoclinic stackings which may prove useful in characterizing magnetic multilayers grown for device applications. 

T00.00069: Effect of the Rashba Spinorbit coupling on Some Dynamic Electronic Properties of Twodimensional Semiconductors Yonatan Abranyos, Godfrey A Gumbs, Danhong Huang, Andrii Iurov We present both theory and computational results for the transmission probability of a charged particle across a potential step in the presence of a Rashba spinorbit interaction. In particular, we examine the conditions under which there could be Klein tunneling which is a phenomenon that has long been of interest to both experimentalists and theoreticians. We also determine Green's functions from which we deduce the spectral functions. These latter quantities are then employed to calculate the frequencydependent optical conductivity. The dependence of the optical conductivity on the spinorbit interaction coupling and step height will be investigated. 
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T00.00070: Effect of Mechanical Strain on the Electronic and Magnetic Properties of UTe 2 Jalen Garner, Kevin F Garrity, Francesca Tavazza, Sugata Chowdhury Unconventional superconductors have challenged current experimental and theoretical understandings of 

T00.00071: Calculating Macroscopic Resistance using Microscopic Reflectance in VO_{2} thin films Amit Rohan R Rajapurohita, Sayan Basak, Forrest Simmons, Nicolas Raymond, Pavel Salev, Ivan K Schuller, Lionel Aigouy, Erica W Carlson, Alexandre Zimmers Vanadium Dioxide (VO_{2}) exhibits multiscale pattern formation while it undergoes a temperaturedriven MetalInsulator (MI) phase transition. We use optical microscopy techniques to image the entire surface of a twoterminal etched VO_{2} microbridge, simultaneously measuring the macroscopic resistance of the device. Patches of metal and insulator form while undergoing the MI phase transition and display hysteresis. We employ a random field Ising model to predict subpixel spatial structure below optical resolution, mapping the reflectivity of each pixel to the Ising pseudomagnetization, in order to predict the effective microscopic resistance of each pixel. We use the (exact) bond propagation algorithm to reduce the 2D resistor grid into a single equivalent resistance. These studies pave the way toward a deeper understanding of resistance avalanches, memory effects, and spiking behavior in VO_{2}. 

T00.00072: Fabrication and Characterization of Thin Film Copper Selenate David King, Jinke Tang, John Ackerman Cu_{2}OSeO_{3} is a cubic chiral ferrimagnet. In addition, it is a magnetic insulator with a magnetic skyrmion lattice phase, making it a promising material for spintronics. Previous research on Cu_{3}OSeO_{3} used only single crystal Cu_{2}OSeO_{3} or thin layers obtained by milling down bulk single crystals. We have successfully fabricated thin film Cu_{2}OSeO_{3} using pulsed laser deposition (PLD) and subsequent solid state reactions. Here, we present our method of thin film fabrication. We also show data characterizing the film specifically the film's crystallography, morphology, and uniformity. 

T00.00073: Superconductivity and Bound States in Topological Models YING WANG We investigate superconductivity in topological structures, such as the twodimensional SuSchriefferHeeger (SSH) model. Depending on the doping concentration, we find regimes of bulk, edge, and corner superconductivity. We examine the pair correlations and the local density of states. In generalized 2D SSH models, hopping pattern variations are shown to induce distinct pairing patterns. Bound states in the bulk are identified and analyzed within the Bogoliubovde Gennes formalism. 

T00.00074: Boundary theory of the Xcube model: a continuum perspective ZhuXi Luo, Ryan C Spieler, HaoYu Sun, Andreas Karch We study the boundary theory of the Z_{N }Xcube fracton model using the continuum field theory description. Different gapped boundary conditions are discussed and the corresponding ground state degeneracies (GSD) are presented. Interestingly, the extensive part in the GSD varies with the boundary conditions. 

T00.00075: Effect of pressure on the valence transition in CeOs_{4}Sb_{12} PeiChun Ho, Kathrin Goetze, Matthew J Pearce, Matthew J Coak, Paul A Goddard, Audrey D Grockowiak, David E Graf, Stanley W Tozer, M Brian Maple, John Singleton At low temperatures T, the filled skutterudite CeOs_{4}Sb_{12 }is a heavyfermion compensated semimetal. It also exhibits a ~1 K SpinDensityWave (SDW) phase and has been suggested to possess topologically protected states. Penetration depth and resistivity measurements reveal a Fermisurface reconstruction in CeOs_{4}Sb_{12} with an unusual temperature T vs magnetic field H phase diagram that is associated with a valence transition [1,2]. In this report, we present the influence of pressure on the electronic properties and TH phase boundaries of the valence transition and the SDW. Refs: [1] K. Götze et. al, PRB 101, 075102 (2020). [2] P.C. Ho et. al, PRB 94, 205140 (2016). 

T00.00076: Permanent manipulation of polar textures in thin ferroelectric films: insights from large scale density functional theory Jack S Baker, David R Bowler Thin ferroelectric (FE) films and superlattices are known to be hosts to complex polarization textures such as polar waves, fluxclosure domains and polar skyrmion phases. While technological uses for these exotic morphologies have been proposed, little is known about how they can be deterministically controlled. Presently, it is possible to temporarily manipulate these textures using precisely directed electric fields. Permanent texture "writing", however, is not achieved. Until now, investigations of polar texture control have been limited to experiment and lower levels of theory. The latter limitation arises from the fact that an accurate quantum mechanical treatment using density functional theory (DFT) is prohibited by the computational effort required. That is, exotic polar textures span length scales encompassing thousands of atoms, well beyond the limitations of traditional O(N^{3}) scaling DFT (where N is the number of atoms). To avoid this scaling wall, we deploy two separate large scale DFT methods implemented in CONQUEST able to simulate to thousands of atoms. Using this method, we study two pathways for permanent polar texture manipulation in the PbTiO_{3}/SrTiO_{3} system: (i) builtin bias fields and (ii) engineered surface defects. For (i), we show that a builtin bias field is present for most polar filmsubstrate heterostructures. Tuning this builtin field allows one to manipulate chiral order on the nanoscale through the careful choice of substrate, surface termination or use of overlayers. For (ii), we investigate the origin of experimentally observed parallel FE domain wall (DW) surface trench (ST) alignment. After explaining this phenomenon with arguments regarding the restoration of polar continuity, we suggest that STs could be used to engineer other exotic polar textures in a variety of FE nanostructures. 

T00.00077: Electronic transport measurements of the airstable ferromagnet Cr_{x}Pt_{1x}Te_{2} Maya H Martinez, Warren L Huey, Joshua E Goldberger, Claudia OjedaAristizabal Van der Waals ferromagnetic materials have recently prompted excitement for their possible device applications. These materials are often highly air sensitive, setting a limit on experimental techniques that allow for the characterization of longrange ferromagnetism in the twodimensional limit. In collaboration with the Goldberger group at The Ohio State University, we study the newly synthesized airstable metallic layered ferromagnet Cr_{x}Pt_{1x}Te_{2}. This novel magnetic random Cralloy has the stability of the transition metal dichalcogenide PtTe_{2}. Flakes of Cr_{x}Pt_{1x}Te_{2} were mechanically exfoliated and characterized through atomic force microscopy and optical imaging. We present preliminary results of electronic transport measurements at low temperatures of quasi twodimensional Cr_{x}Pt_{1x}Te_{2 }crystals. 

T00.00078: Electronic transport measurements of high impedance HeisenbergKitaev materials Patrick T Barfield, Vikram Nagarajan, James G Analytis, Claudia OjedaAristizabal


T00.00079: Novel Electronic Structure Signature across Antiferromagnetic Transition in Rare Earth Monopnictide NdSb Milo X Sprague, Firoza Kabir, Baokai Wang, Anup Pradhan Sakhya, Md Mofazzel Hosen, Sabin Regmi, Gyanendra Dhakal, Klauss M Dimitri, Christopher Sims, Robert H Smith, Eric D Bauer, Filip Ronning, Arun Bansil, Madhab Neupane


T00.00080: Wigner crystalline in PbS moiré superlattices Zhigang Song Recently, moiré superlattices of twisted van der Waal (vdW) materials have attracted a giant interest due to a series of breakthroughs. Since the quantum confinement from vdW interaction is not strong enough due to the weak interaction, a series of important properties are missed. Strong reconstruction and deep energy levels are desired due to the potential applications in devices and novel physics different from vdW layers. Benefited from the strong interaction, we predict a new species of twisted nanosheets beyond vdW materials. Such a crazy structure is confirmed by our TEM experiment. Combined with DFT calculation, we find a series of strain vertex and dipole vertex at the interface. If the materials are doped with a low concentration of electrons, different phases of Wigner crystalline will form even without any magnetic field. These properties can be applied in novel devices. 

T00.00081: Atomistic Simulations of Defects in Silicon Carbide Ananya Chakravarti, Elizabeth M Lee, Juan De Pablo Spin defects in silicon carbide (SiC) are desirable platforms to create quantum technologies, such as quantum sensing, communication, and metrology. Notable spin defects are divacancies, which are formed when a silicon and carbon atom adjacent to one another are removed, generating a vacancy complex. Despite their importance, divacancies have been challenging to controllably synthesize experimentally. Here, we provide computational investigations into defect migration phenomena in 4HSiC, a common polytype that is used experimentally but has not been studied theoretically. We employ classical and ab initio approaches to study the dependence of defect migration and formation on crystal structure, temperature, and defect concentration. We find that the choice of classical force field affects the melting behavior of 4HSiC. We also find that vacancy migration occurs at an increased frequency for higher defect concentrations. Finally, we show how the crystal symmetry impacts the defect migration behavior across a range of temperatures, using both classical force fields and density functional theory (DFT) calculations. 

T00.00082: Topological Antiferromagnetic Phase of NiIntercalated Bi2Te3 in Sputtered Topological Insulator/FerromagnetBi2Te3/Ni80Fe20 Heterostructures Nirjhar Bhattacharjee, Krishnamurthy Mahalingam, Adrian Fedorko, Valeria Lauter, Matthew E Matzelle, Bahadur Singh, Alexander Grutter, Alexandria WillCole, Michael R Page, Michael McConney, Robert S Markiewicz, Arun Bansil, Donald E Heiman, Nian X Sun The MBi_{2}Te_{4} (M = Mn, Ni, Eu, V) family of compounds has recently shown promise as an intrinsic magnetic topological insulator (MTI), capable of supporting the quantum anomalous Hall (QAH) effect. Here, we report: (i) Growth of highquality caxis oriented TI, Bi_{2}Te_{3} (BT) using sputtering; (ii) Emergence of an interfacial topological antiferromagnetic (AFM) phase when BT is coupled with ferromagnetic materials (FM) such as Ni_{80}Fe_{20} (Py) [1] and Ni_{x}Zn_{y}(FeO_{2})_{z} (NiZnFr) [2]. Ni diffuses across the interface and forms a Niintercalated BT (Bi_{2}Te_{3}:Ni) phase. Magnetic hysteresis loop measured at 6K revealed a significant exchange bias (EB) of ~80 Oe and ~5 Oe in BT/Py and BT/TiOx/NiZnFr heterostructures confirming FM/AFM interaction. The observation of EB was supported by evidence of AFM order using polarized neutron reflectometry in the Bi2Te3:Ni layer. Crosssectional chemical analysis using EELS and XPS techniques showed evidence of solidstate reaction between Ni and BT to form NiTe bonds. The Neél temperature of the AFM phase was ~63 K, which is higher than that of typical magnetic TIs (MTI). These results pave the way for the exploration of topological phases in CMOSprocesscompatible sputtered TI/FM heterostructures and interfaces. 

T00.00083: Absorption coefficient study for Al_{x}Ga_{1x}As Konwent quantum well potential profile as a function of electric, magnetic, and intense laser field effects. Juan Carlos Martinez Orozco, F. Ungan, K.A. RodríguezMagdaleno, F. M. NavaMaldonado Optoelectronic properties for semiconductor quantum wells are among the most studied systems in solid state physics devices. Nevertheless, this is a topic that deserves attention because the quantum well (QW) shape than can consider important physical facts as the impurity diffusion, that in combination with external factors as electromagnetic fields or intense laser field effects, allows to investigate possible new behaviors for the optical properties of interest. In this line, we consider an Al_{x}Ga_{1x}As quantum well potential profile given by the Konwent potential, that as a function of the parameters can generate a single or double QW than can be shaped with the aluminum concentration. In this study we compute the electronic structure for system by working within the effective mass approximation for solving the oneelectron Schrodinger equation, we report the absorption coefficient for the system as a function of the parameters of the Konwent potential. Then, we investigate the effect of an electric field applied in the confinement direction (z) as well as an inplane (xdirected) constant magnetic field. Finally, we also investigate the effect of a nonresonant intense laser field effect on the system. Here we can conclude that the Konwent potential parameters allow to tune the optical properties for energies ranging from 20 up to 100 meV; that the electric field induces a blueshift, and a diminishing of the intensity, for the optical response; that the magnetic field also indices a small blueshift, but practically without intensity lost; and that the intense laser field also induces a stronger blueshift, as well as increase in the optical response. 

T00.00084: Highfrequency electroluminescence of TMD heterostructures. Shaina Raklyar, Milan Begliarbekov, Gabriele Grosso, German Kolmakov Transferring data from quantum computer processing units to end users is challenging technological problem due to the low energy consumption and high data rate requirements. Due to their unique properties, transitional metal dichalcogenides (TMD) heterostructures are promising candidates for designing cryogenic electrooptical conversion devices, which could be used in such connection. We present the results of our studies of electroluminescence of molybdenum diselenidetungsten disulfide heterostructures at helium temperatures. The heterostructures have been produces by the exfoliation. The spectrum of electroluminescence is analyzed in a broad range of temperatures and input electric signal frequencies. Our experimental results are supplemented by theoretical modeling of the system. We also discuss application of the obtained results to electrooptical converters to be used in quantum computing data transfer systems. 

T00.00085: Coulomb Blockade Phenomena in Random Telegraph Noise of a commercial 28nm PMOS HeeBong Yang, Marcel J Robitaille, Xuesong Chen, Hazem Elgabra, Lan Wei, Na Young Kim A quantum dot (QD) is a zerodimensional nanostructure that can be one of the candidate platforms to implement the quantum computing in semiconductors as quantum bits (qubits). Specifically, QDs in the metaloxidesemiconductor fieldeffect transistors are created readily as fabrication facilities and processes are already mature, and the QD platform controlling qubits is promising for a large number of qubits scaledup system. However, some QD transport features by gatecontrolled MOSFETs are typically observed dilution refrigerator temperatures. In this presentation, we examined QD phenomena with a foundry 28nm PMOS transistor even at 14 K and performed systematic noise analysis of the random telegraph noise (RTN). The Coulomb blockade phenomenon is shown as a hump in DC transfer curves nearthreshold voltage due to the resonant tunneling. Gatevoltage dependent measurements show consistent trends between RTN noise parameters and these trends tell us the minimum noise point where the peak of Coulomb blockade region in the DC transfer curves which can help to design cryogenic devices. 

T00.00086: Ultrafast fielddriven valley polarization in TMDC quantum dots ARANYO MITRA, Vadym Apalkov, Ahmal Jawad Zafar, Seyyedeh Azar Oliaei Motlagh We study theoretically interaction of circularly polarized ultrashort and ultrafast optical pulse with transition metal dichalcogenide (TMDC) quantum dots. Quantum dots are described within an effective model and have a shape of a disk. The duration of the pulse is a few femtoseconds, and the electron dynamics in the field of such pulse is coherent. We study the valley polarization generated after a circularly polarized pulse. The valley polarization is defined as the difference in conduction band populations of the K and K' valleys of TMDC quantum dots. The valley polarization depends both on the size of the dot, i.e., its radius, and on the amplitude of the pulse field. The valley polarization decreases with increasing the size of the dot. Such dependence can be related to the dependence of the quantum dot bandgap on the radius of the dot. The valley polarization of a TMDC quantum dot has nonmonotonic dependence on the field amplitude, where the maximum valley polarization is realized at a finite field amplitude around 0.1 V/A. 

T00.00087: Valley polarization in graphene quantum rings by ultrafast optical pulse Ahmal J Zafar, Vadym Apalkov, Aranyo Mitra, S. Azar Oliaei Motlagh We study theoretically electron dynamics in graphene quantum rings placed in an ultrashort and strong optical pulse. We describe the graphene quantum rings within an effective model with an infinite mass boundaries. For the optical pulse with the duration of just a few femtoseconds the electron dynamics is coherent and is described by the timedependent Schrodinger equation. If the optical pulse is circularly polarized then two valleys of graphene nano ring, K and K’, are populated differently after the pulse resulting in finite valley polarization of the system. This is a unique property of graphene nanoscale systems, while for graphene monolayer the circularly polarized pulse does not produce any valley polarization. The valley polarization of the graphene nano ring depends on the parameters of the system, such as inner and outer radii. For small field amplitudes, we interpolate this dependence and obtain an analytical expression for the valley polarization of any graphene quantum ring with sizes up to 50 nm. This expression could be used to design a system, which can produce a given valley polarization. Our findings are useful in nanostructure designs for information storage and processing. 

T00.00088: de Gennes Narrowinglike Phenomenon and Nanoripple Velocity Measurement in SelfOrganized IonBeam Nanopatterning Peco Myint, Karl Ludwig, Xiaozhi Zhang, Lutz Wiegart, Yugang Zhang, Andrei Fluerasu, Randall L Headrick Realtime coherent GrazingIncidence SmallAngle Xray Scattering (GISAXS) was utilized to investigate the kinetics and the fluctuation dynamics during ion beam nanopatterning. Initially flat silicon samples at room temperature were bombarded by a broad collimated beam of 1keV Ar^{+} or Kr^{+} ions at 65° polar angle, leading to the amorphization of the ionirradiated surfaces and the spontaneous formation of nanoscale ripples. The temporal evolution of the average Xray scattering intensity in GISAXS data shows the evolution of kinetics, whereas Xray Photon Correlation Spectroscopy (XPCS) calculations help explain the fluctuation dynamics. The surface behavior at early times can be explained within a linear theory framework, but the behavior becomes highly nonlinear since the intensity correlation function evolves into a compressed exponential decay on length scales corresponding to the peak ripple wavelength and a stretched exponential decay on other length scales. The correlation times for silicon nanopatterning are maximum at the ripple wavelengths while they are smaller at other wavelengths: a phenomenon that is reminiscent of the phenomenon of de Gennes narrowing observed in a wide range of soft materials. Overall, such dynamic behavior is found to be consistent with the simulations based on a nonlinear growth model. Following the formation of selforganized nanoripples, they move across the surface. While homodyne XPCS is not sensitive to such nanoscale movements, because of the gradient of ion flux across the sample, we were able to measure the ripple velocity gradients by crosscorrelating Xray speckles and tracking their movements. 

T00.00089: Effects of strain on the electronic and phononic properties of Fe intercalated TaS_{2} using density functional theory Drew Duncan, Janice Musfeldt, Jason T Haraldsen Intercalated metal monolayers have interesting electronic, magnetic, and phononic properties that may provide potential technological applications. In this study, we examine the effects of stress and strain on the properties of Fe intercalated TaS2. Using density functional theory, we determine the electronic band structure, density of states, and phonon spectra for 2HTaS2, Fe_{1/4}TaS2, and Fe_{1/3}TaS2 and the effects of isotropic and uniaxial strain. Through an analysis of the systems, we show how stress shifts the phononic modes of the Fe atoms. 

T00.00090: Topological edge states of Bi(110) islands on top of highTc superconductor Zengyi Du, Hui Li, Asish K Kundu, ZeBin Wu, Abhay N Pasupathy, Ilya K Drozdov, Kazuhiro Fujita Recent Scanning Tunnelling Microscopy (STM) measurements showed that elemental bismuth hosts topological electronic states on both Bi(111) [1,2]and Bi(110) facets [3]. The question of higherorder topology (HOT) in bismuth is still a highly debatable matter [4]. Here we synthesized a Bi(110) thin film by molecular beam epitaxy on the cleaved extremely overdoped Bi_{2}Sr_{2}CaCu_{2}O_{8+δ} substrate and performed STM measurements on it. We observed Bi rectangular islands with (110) facet in which 1D edge state appears only on two or three out of four edges. Theoretically, this can be consistent with one of the phases with HOT, but it is also consistent with the geometrical properties of the edges [1]. Interestingly, we found an ‘L’ shaped island where two Bi(110) domains are merging together, and identified a 1D state propagating along the boundary at the same energy as the edge states. In this talk, we will discuss a possible topological nature of this edge state and its relation to the highTc superconducting proximity effect from the Bi_{2}Sr_{2}CaCu_{2}O_{8+δ} substrate. 

T00.00091: Continuously Tunable 2D GalliumIndium Alloys Benjamin Katz, Vincent H Crespi, Siavash Rajabpour, Alexander Vera, Wen He, Margaux Lassaunière, Hesham ElSherif A novel technique for achieving 2D metal layers – Confinement Heteroepitaxy (CHet) [1] – has recently been extended to metallic alloys [2]. We report here the structural energetics, electronic properties, and structural trends in CHetbased Indium/Gallium alloys, identifying trends that may generalize to other 2D metallic alloys that also form continuously tunable alloys. In particular, a rapid reduction in the superconducting transition temperature with increasing indium fraction appears to correlate to the depletion of carrier pockets that participate strongly in the superconductivity of pure 2D Gallium. 

T00.00092: Transient SecondOrder Optical Nonlinearity Induced by HotElectron Transport Mohammad Taghinejad, Zihao Xu, Kyutae Lee, Andrew Kim, Mark Brongersma, Tianquan Lian, Wenshan Cai Secondorder optical effects are essential to the active control of light and the generation of new spectral components via nonlinear processes such as secondharmonic generation, sum/difference harmonic generation, Pockels effect, and optical parametric oscillation. The portfolio of Chi2 media, however, is rather limited as the inversion symmetry in most optical materials prevents achieving a nontrivial Chi2 response, under the electric dipole approximation. It is a longstanding challenge and pressing need to address this fundamental constraint and enable secondorder nonlinearities in semiconductors and oxides that dominate the optoelectronics arena. Here, we present a new scheme for breaking the inversion symmetry and enabling Chi2 processes via the generation and transport of hot electrons. The subpicosecond kinetics of hot carriers enables the ultrafast conversion of staticallypassive oxides into transient secondorder nonlinear media, immediately expanding the portfolio of Chi2 materials beyond the family of conventional nonlinear crystals. In addition, the proposed scheme could be considered as a nonlinear optical probe to monitor the dynamics of interfacial charge transport in hybrid metal/dielectric material platforms. 

T00.00093: Polarized Reflectivity of Weyl Semimetals in the Near and MidInfrared using a Liquid Crystal Variable Retarder Giriraj Jnawali, Craig Street, Fawaz Albalawi We show that one can use a Liquid Crystal Variable Retarder to achieve complete control over the linear or circular polarization of light from a pulsed laser which ranges from 680 nm to 4000 nm (1.8 eV to 0.3 eV). It is thus possible to continuously tune the four relevant polarizations x>, y>, σ+> and σ> over this entire energy range and so extract the polarized reflectivity from a number of materials. We show how to calibrate such a system and show as examples polarized reflectivity spectra for a number of Weyl semimetals. 

T00.00094: Quantum buckling in metalorganic framework materials R. Matthias Geilhufe Metal organic frameworks are porous materials composed of metal ions or clusters coordinated by organic molecules. As a response to applied uniaxial pressure, molecules of straight shape in the framework start to buckle. Under sufficiently low temperatures, this buckling is of quantum nature, described by a superposition of degenerate buckling states. Buckling states of adjacent molecules couple in a transverse Ising type behavior. On the example of the metal organic framework topology MOFV we derive the phase diagram under applied strain, showing a normal, a parabuckling, and a ferrobuckling phase. At zero temperature, quantum phase transitions between the three phases can be induced by strain. This novel type of order opens a new path towards strain induced quantum phases. 

T00.00095: Spin transport driven by strong spin orbit coupling at 2dimensional conducting SrTiO_{3} surface MiJin Jin The field of spintronics now goes beyond the injection and detection of electron spins, and expands and diversifies into new opportunities such as spincaloritronics of spin and magnon, spinorbitronics using spin orbital coupling, and spinterface using spin at the material interface. Here we bypass the problem by generating a spin current not through the spin injection from outside but instead through the inherent spin Hall effect, and demonstrate the nonlocal spin transport. The analysis on the nonlocal spin voltage, confirmed by the signature of a Larmor spin precession and its length dependence. We report nonlocal spintransport on twodimensional surfaceconducting SrTiO_{3} (STO) without a ferromagnetic spin injector via the spin Hall effect (and inverse spinHall effect). By applying magnetic fields to the Hall bars at different angles to the nonlocal spindiffusion, we demonstrate an anisotropic spinsignal that is consistent with a Hanle precession of a pure spin current. 

T00.00096: Quantum Oscillations from Surface States in Cd_{3}As_{2}Nanowires Yu Miyazaki, Tomoyuki Yokouchi, Kiyou Shibata, Yao Chen, Hiroki Arisawa, Teruyasu Mizoguchi, Eiji Saitoh, Yuki Shiomi Topological Dirac and Weyl semimetals have topological surface states called Fermi arcs. Extensive efforts have been made toward the observation of novel topological transport phenomena induced by the Fermi arc. However, surfacestateinduced quantum oscillations have not been demonstrated in nanowires of TDSMs. Here, we report the observation of surface Shubnikovde Haas oscillations in submicron wires of TDSM Cd_{3}As_{2} grown by a chemical vapor deposition method. Our results will facilitate the further study of quantum transport phenomena in topological nanowires. 

T00.00097: Charge accumulation driven by pseudohydrodynamics of quasiparticles in a semimetal WTe_{2} at room temperature YoungGwan Choi, ManhHa Doan, Maxim Chernodub, GyungMin Choi Currently, the hydrodynamic behavior of carriers has been attracting much interest. For example, the ultraclean graphene can show a hydrodynamic charge flow, when momentum conserving carriercarrier scattering is dominant than other scatterings, e.g. whirlpool structure similar with flowing water. The vortices indicates the back flow of the current resulting in a negative nonlocal voltage near current sources and drains. For example, the negativepositivenegative patterns in the voltage near the contacts can be utilize as an evidence of experimentally signature of the electronic viscous behavior. 

T00.00098: Superconductivity in Chemically Doped TypeII Weyl Semimetal MANASI MANDAL, R. P. Singh The discovery of superconductivity in layered transition metal dichalcogenides offers a fascinating opportunity to explore superconductivity and possible topological states by tuning the local structural distortion or manipulating chemical pressure. We have studied the exotic typeII Weyl semimetal MoTe_{2} system by chemical doping. Re/Ir substitution in Mosite in MoTe_{2} is doping electrons and facilitates superconductivity by increasing the electronphonon coupling and density of states at the Fermi level. Chiral anomaly induced planar Hall effect and anisotropic magnetoresistance confirm the topological semimetallic nature of Mo_{1−x}Ir_{x}Te_{2}. Observation of moderately coupled typeII superconductivity in T_{d}Mo_{1−x}(Ir/Re)_{x}Te_{2} makes it a promising candidate for a topological superconductor. Therefore, our findings of superconductivity by chemically doping in Weyl semimetal extend the territory for exploring unconventional superconductors with possible topological states. 

T00.00099: Proximity effects and topological superconductivity dependency on layer thickness in superconductor/ferromagnetic/semiconductor hybrid devices Samuel D. D Escribano, Ruben Seoane Souto, Andrea Maiani, Martin Leijnse, Yuval Oreg, Alfredo Levy Yeyati, Karsten Flensberg, Elsa Prada We investigate the topological properties of hybrid devices made of a semiconductor wire partially covered by a ferromagnetic layer, which in turn is covered by a superconducting one (i.e., the wire and the superconductor layer are not directly in contact). We perform numerical calculations of the system including the three materials and the electrostatic environment, and we analyze how its properties change with the ferromagnetic layer width and the gate potentials. We show that both proximity effects into the wire, the induced superconductivity and the induced exchange field, strongly depends on the ferromagnetic layer thickness. We therefore find a suitable thickness range for which the system can support topological phases, and particularly the socalled Majorana bound states. We also perform the same analysis for a semiconducting 2DEG finding similar results, although the topological phases turn out to be more robust. 

T00.00100: Computational Study of Electronic Structure and Transport Properties of PAl_{12}Based Nanocluster Complexes Haiying He, John Shen, Turbasu Sengupta, Dinesh Bista, Arthur C Reber, Ravindra Pandey, Shiv N Khanna Rational design and fabrication of nanoscale devices take the center stage in the current era of information science and technology. In this study, we propose using semiconducting cluster complexes constituted of atomic clusters and choices of ligands as crucial components in electronic devices. The electronic structure and transport properties of PAl_{12}based nanocluster complexes are investigated by density functional theory (DFT) in combination with the nonequilibrium Green’s function (NEGF) method. Joining two PAl_{12} clusters via a germanium linker creates a stable semiconducting complex with a large HOMO−LUMO gap. Sequential attachment of an electrondonating ligand, Nethyl2pyrrolidone, to one of the two linked clusters results in the shifting of the electronic spectrum of the ligated cluster while the energy levels of the unligated cluster are mostly unchanged. As a result, the transport properties of the complex are highly dependent on the number of attached ligands. This dependence is discussed in light of the nature and location of molecular orbitals, the coupling to the electrodes, and the delocalization of the resultant transmission orbitals. 

T00.00101: Compatibility of transport effects in nonHermitian tightbinding models Hamed Ghaemidizicheh In this talk, we show conditions for effects such as reflectionless and transparent transport, lasing, and coherent perfect absorption in nonHermitian topological model. We then identify which effects are compatible and linked with each other and determine by which levers they can be tuned independently. 

T00.00102: General properties of fidelity susceptibility in nonHermitian systems with PTsymmetry PoYao Chang, YuChin Tzeng, YiTing Tu, Iksu Jang We systematically derive the general properties of the fidelity susceptibility defined by the left and right manybody eigenstates of nonHermitian Hamiltonian with the combination of parity and timereversal symmetries (PTsymmetry). In the spontaneous PTsymmetry broken phase, we prove the fidelity susceptibility is real and diverges to negative infinity as the parameter approaches the exceptional points (EPs). This divergence leads to a significant enhancement of the fidelity susceptibility near the phase transition point in a Hermitian system with small nonHermitian perturbations, where the phase transition point splits into a pair of EPs. We demonstrate these behaviors by the twolegged SuSchriefferHeeger model with PT nonHermitian perturbations. In addition, we find there is an emergent PTsymmetric region from the PT broken phase due to the finite size effect. 

T00.00103: Effect of dilute magnetism in a topological insulator Firoza Kabir, Iftakhar Bin Elius, Md Mofazzel Hosen, Xiaxin Ding, Christopher A Lane, Gyanendra Dhakal, Yangyang Liu, Klauss M Dimitri, Christopher Sims, Sabin Regmi, Anup Pradhan Sakhya, Luis E Persaud, John E Beetar, Yong Liu, Michael Chini, Arjun K Pathak, JianXin Zhu, Madhab Neupane, Krzysztof Gofryk Threedimensional topological insulator (TI) has emerged as a unique state of quantum matter and 

T00.00104: Surface Analysis of DMATMS Molecules Adsorbed on SiO_{2}/Si Substrates for Area Selective Deposition Anthony Valenti, Christophe Vallé, Carl A Ventrice Area selective deposition is used by the semiconductor industry for bottomup manufacturing of semiconductor devices. With this technique, a molecular film adsorbs to regions of the substrate that you would like to block from adsorption of another species. Dimethylaminotrimethylsilane (DMATMS) has a strong affinity for adsorption on SiO_{2} surfaces and low affinity for adsorption on most metal surfaces. Therefore, it can be used to block deposition of metals on SiO_{2}, while allowing deposition of metals on metals. Samples of DMATMS adsorbed on Si(100) substrates with a 1000 Å thermal oxide and various surface pretreatments have been prepared. Surface pretreatments include ozone exposure, H_{2} plasma treatment, or H_{2} plasma pretreatment followed by H_{2}O vapor exposure after DMATMS absorption. Spectroscopic ellipsometry, FTIR spectroscopy, XPS, and TPD are being used to determine the surface coverage and temperature stability of the DMATMS molecules after surface pretreatment. 

T00.00105: SelfAssembly of Nanoparticles Induced by Polymer Brushes Eric J Spangler, Mohamed Laradji, Jacob Mims The ability to assemble nanoparticles (NPs) into ordered superstructures is important to the development of devices for a range of applications including energy harvesting and storage, magnetic storage, plasmonics, electronics, drugdelivery, catalysis, imaging, and biosensing. While assemblies of NPs into various structures can be obtained through topdown approaches such as lithography, these techniques require precise placement of the NPs, which relies on careful calibration and clean environment. These techniques also suffer from a range of limitations including the synthesis of structures with characteristic length scales smaller than ~10 nm. Using molecular dynamics simulations of a coarsegrained implicitsolvent model, we show that polymer brushes in good solvent conditions can mediate the selfassembly of spherical NPs into ordered hexagonallyclosepacked superstructures over a wide range of NPpolymer interactions. We show that these structures are the result of the chains' conformational anisotropy and gradients in the polymer density profile. 

T00.00106: Stability, Metallicity, and Magnetism in Niobium Silicide Nanofilms Xuezeng Lu, Dominic P Goronzy, Carlos G TorresCastanedo, Paul M Das, Maryam KazemzadehAtoufi, Peter W Voorhees, Vinayak P Dravid, Mark C Hersam, James M Rondinelli Modern superconducting charge qubits based on transmons involve the growth of niobium thin films on resistive silicon substrates under variable processing conditions. The atomic precision of the NbSi heterointerface can limit qubitcoherence times. Bulk binary intermetallic niobium silicide phases exhibit a range of stable compositions that are often processed at high temperature; however, the thermodynamic phase stability and properties of possible ultrathin silicides, such as those that form at the NbSi heterointerface during deposition, have not yet been reported. Here we report the first ab initiobased finitesize effect studies and predict a novel nonequilibrium silicide stabilized at the nanoscale. This result is consistent with our direct experimental growth of the silicide from a bulk Nb source by pulsed laser deposition. We also find the surfaces of the silicides are magnetic, which may lead to an additional dissipation channel. Our work suggests that NbSi heterointerfaces in transmons may not be atomically sharp and interfacial composition and morphology have important implications on achieving long qubitcoherence times. 

T00.00107: Radiative Dynamics of Thermalized Excitons at Metal Interfaces Grace H Chen Exciton dynamics in monolayer transition metal dichalcogenides (TMDCs) have garnered recent interest as a platform for optoelectronic devices and are often placed near metal interfaces or inside planar cavities. We compare the emission properties of excitons–which are fundamentally delocalized–in TMDCs near planar metal interfaces to point dipoles and explore their dependence on exciton centerofmass momentum, transition dipole orientation, and temperature. In regimes where the momentum distribution can be characterized by MaxwellBoltzmann statistics, the modified emission rates (normalized to free space) behave similarly to point dipoles due to the broad nature of wavevector components making up the exciton and point dipole emission. Conversely, the narrow momentum distribution of excitons at low temperatures results in significantly different emission behavior compared to point dipoles. At high phase space densities, excitons characterized by BoseEinstein statistics exhibit modified emission rates that can be suppressed or enhanced relative to point dipoles by several orders of magnitude. These insights can help optimize optoelectronic devices that incorporate TMDCs near metal interfaces and can inform future studies of low temperature exciton radiative dynamics. 

T00.00108: Straindependent properties of Singleelectron transistor based on Bi_{2}Se_{3}_{ }island. SHANTANU MAJUMDER Bi_{2}Se_{3} is a wellknown individual from the twodimensional materials family for its topological insulator and thermoelectric properties, and because of this it has an enormous possibility in future nanoelectronics. Here, we have exhibited the activity and execution of a Bi_{2}Se_{3} island Singleelectron transistor (SET) by using firstprinciple calculation. Additionally, we expanded our work by applying both compressive and tensile strain and checking the effect on the performance of SET. For unstrained configuration, we obtained the electrostatic coupling parameter between the gate and the island (α) and the electrostatic polarisation contribution parameter (β) of the island towards the total energy to be 0.38037 and 0.05042 eV^{1} where the transport direction is along the ‘x’ direction. As we varied the strain the lowest value of α was obtained at 3% strain and β decreased as we increased the strain. The charge strength outline fluctuated by the strain applied and their effect can be deduced from line examines and normalized differential conductance. 

T00.00109: Vortices and phase transitions in a superconductor with repulsive interactions Dimitri Pimenov, Andrey V Chubukov, Morten Holm Christensen We analyze the structure of an swave superconducting gap in systems with electronphonon attraction and electronelectron repulsion. Earlier works have found that superconductivity develops despite strong repulsion, but the gap necessarily changes sign along the Matsubara axis. We analyze the signchanging gap function from a topological perspective using the knowledge that a nodal point is the center of dynamical vortex. We consider two models of repulsive interaction and trace the vortex positions along the Matsubara axis and in the upper frequency half plane upon changing the relative strength of the attractive and repulsive 

T00.00110: Dipolar lineons in a holedoped collinear antiferromagnet Sambuddha Sanyal, Alexander Wietek, John Sous Fractons are emergent quasiparticles, which have fractionalized (reduced) mobility. In this talk we demonstrate the emergence of fracton conservation laws in a holedoped collinear antiferromagnet in two dimensions. Using a combination of analytical and numerical approaches we show that these systems host fractonlike quasiparticles, which are completely immobile in isolation, and dipolar quasiparticles that can move freely only along one dimensional subspace of the system. We discuss possible experimental realizations of these observations. 

T00.00111: Tuning Interlayer Excitons in 2D Semiconducting Heterostructures by Interfacial Charge Transfer Jong Hyun Choi, Jaehoon Ji Atomically thin heterostructures from transition metal dichalcogenides (TMDs) show a new class of quasiparticle (i.e., interlayer exciton or IX) with promising optoelectronic properties for next generation excitonic devices and spintronics. To realize the advanced applications, the precise control of the characteristics of IX is necessary. This work introduces a new strategy to control IX selectively by integrating organic layers on top of atomically thin TMD heterostructures. The organic layers form various energy level alignments with monolayer TMDs. Under light illumination, the organic layers regulate the photoinduced charge transfer process at the interfaces. Regardless of irradiation, they may also give rise to darkstate doping on the heterostructure. Depending on the interlayer charge transfer pathways, the emission originating from the radiative recombination of IX can be preserved intact, completely quenched, or moderately modulated. The results also suggest that the IX emission may be predominantly determined by the photoinduced process over darkstate doping. These findings shed critical insights on the nature of IX and advance the realization of IXbased devices. 

T00.00112: Proximal CDW instabilities and collective modes of weakly disordered swave superconductors Prathyush P Poduval, Abhisek Samanta, Nandini Trivedi, Rajdeep Sensarma We investigate the effect of weak disorder on low energy collective modes of a disordered swave superconductor on a square lattice. We find that near halffilling, the joint presence of disorder and nearby charge density wave instability causes static density and pairing fluctuations centred around $[\pi, \pi]$. These static fluctuations due to disorder couple to the dynamic quantum fluctuations (collective modes) producing subgap spectral weight in the process. Using a simplified two mode model, we analytically understand the frequency and nature (Higgs vs phase character) of the subgap mode at $q=[0,0]$ and their variation with density and particlehole symmetry breaking terms in the Hamiltonian. We also understand why inclusion of quantum density fluctuations lowers the energy of the subgap mode and leads to a broad feature in the two particle spectral function at low energies. 

T00.00113: Electronic Structure and ExcitedState Dynamics of StronglyCoupled CyanineBased Aggregates Templated Using DNA Jonathan S Huff, Daniel B Turner, Bernard Yurke, William B Knowlton, Paul H Davis, Ryan D Pensack Supramolecular assemblies of dye molecules, known as dye aggregates, are of great interest for applications in light harvesting, nanoscale computing, and energy conversion, among others. This broad interest in dye aggregates stems from the unique and tunable electronic and optical properties they exhibit, which are sensitive to structural parameters including interdye separation and orientation. An emerging strategy for controlling dye aggregate properties is to assemble them using DNA nanostructures as a template. In recent years, DNA templating has facilitated systematic investigations of the relationship between aggregate structural parameters and properties. Here we elucidate electronic structure and excited statedynamics in a broad survey of DNAtemplated cyanine aggregates. We show that, in general, strongly coupled cyaninebased aggregates templated using DNA exhibit drastically reduced excitedstate lifetimes relative to their respective monomers. We find that the reduced excitedstate lifetimes result from enhanced nonradiative decay. We discuss potential mechanisms to explain the enhanced nonradiative decay and ways that it might be suppressed or further enhanced in accordance with the demands of various applications. 

T00.00114: Properties of Cr_{5}Te_{8}/WSe_{2}  2D transitionmetal dichalcogenidesbased ferromagnetic heterostructures Renat Sabirianov, Hao Zeng, Mengying Bian, Liang Zhu, Chang Huai, Austin Marga, Junhao Lin Cr_{5}Te_{8}/WSe_{2} superlattices, consisting of 2D Cr_{5}Te_{8} conducting magnet with perpendicular anisotropy and a monolayer WSe_{2} investigated using DFT. We show that Cr_{5}Te_{8} maintain its ferromagnetic coupling within CrTe_{2} layer making a case of proximity effect studies. Fermi energy falls within the WSe_{2} bandgap. We observe that conduction band of WSe_{2} is located closer to the Fermi level on the energy scale than the valence band. There is overall charge transfer of 0.18e across the interface from Cr_{5}Te_{8} towards WSe2. Due to the presence of Cr at the interface, the CrSe bonds form that strongly affect the charge redistribution and can be detected by differential charge density. Bader charge analysis show that interfacial Cr sites have larger electron charge compared to the bulk counterparts. The obvious charge coupling between two subsystems may prevent clear observation of photoluminescence in the heterostructure. 

T00.00115: Engineering NiobiumGermanium Interfaces for VoltageTunable Quantum Devices Kasra Sardashti, Bernardo J Langa, Allie M Lindler Voltagetunable hybrid superconductorsemiconductor Josephson junctions have recently emerged as promising building blocks for lowloss frequencytunable quantum devices such as qubits, couplers and magnetic flux sensors. Realization of hybrid devices in group IV semiconductors such as Si and Ge is of particular interest due to higher scalability and low dielectric loss at microwave frequencies. However, inducing superconductivity in Si and Ge via proximity effect has been proven to be challenging so far because of large interfacial energy barriers and defect densities. Here, we utilize molecular beam epitaxy to engineer the energy bands at NbGe interfaces. By creating a gradient in Nb:Ga ratio throughout the superconducting layers, we create smooth potential gradients at the interfaces. Various thermal cycling schemes under vacuum and in inert atmospheres are used for tuning the interface structures. Using highresolution transmission electron microscopy we determine the competing secondary phases that may form in the stacks. This is complemented by cryogenic magnetotransport measurements on the resulting Nb/Ge heterostructures (as films and Josephson junctions) where critical physical parameters including the induced gap size, the critical magnetic field and the normal coherence length for the proximitized phases are determined. 

T00.00116: Coherence Time Enhancement of Interacting Two Level Systems in Aluminum Superconducting Resonators Steven M Anlage, Jingnan Cai We investigate halfwavelength aluminum (Al) coplanar waveguide (CPW) resonators on sapphire substrates under microwave exciation in the superconducting state under conditions typical of superconducting quantum computing applications. Measured temperature dependent and photon number dependent intrinsic quality factor Q_{i}(T) and resonance frequency shift ? f(T) of these resonators are quantitively analized by applying the theoretical tunneling model of two level systems (TLS) along with the combination of equilibrium and nonequalibrium quasiparticles loss models. An unusual increase of intrinsic quality factor Q_{i}(T) with decreasing temperature is observed at ultra low power ( ~ one microwave photon) and low temperature (T). This behavior is attributed to the increase of TLS coherence time (T_{2}), which is propotial to 1/T at ultralow temperatures and powers. 

T00.00117: Synthesis of Mn_{3}Ge and other MnGe phases by molecular beam epitaxy Prajwal M Laxmeesha, Paul C Rogge, Steven J May Binary MnGe alloys are thought to support a wide range of interesting electronic and magnetic phenomena, such as novel spinorbittorques, Berrycurvature driven anomalous Hall effect, and magnetovolume effects, which play an important role in the realization of spintronic devices. Here we report the molecular beam epitaxy growth, on insulating oxide substrates, of numerous stable phases in this system: D0_{22}Mn_{3}Ge, D0_{19}Mn_{3+x}Ge, Mn_{5}Ge_{2}, and an epitaxially stabilized Mn_{5+y}Ge phase that has not been reported before. Rutherford backscattering spectrometry confirmed the film compositions, while variable temperature resistivity measurements revealed metallicity for all phases. The observed ferrimagnetism in D0_{22}Mn_{3}Ge and Mn_{5}Ge_{2} adheres closely to bulk behavior, while much smaller magnetizations are observed in D0_{19}Mn_{3}Ge and Mn_{5+y}Ge films, consistent with antiferromagnetic ordering. 

T00.00118: Ultrasensitive Calorimetric Measurements of the Electronic Heat Capacity of Graphene Aamir Mohammed Ali, John N Moore, Xiaobo Lu, Paul Seifert, Dirk Englund, Kin Chung Fong, Dmitri K Efetov Heat capacity is an invaluable quantity in condensed matter physics and yet has been completely inaccessible in twodimensional (2D) van der Waals (vdW) materials, owing to their ultrafast thermal relaxation times and the lack of suitable nanoscale thermometers. Here, we demonstrate a novel thermal relaxation calorimetry scheme that allows the first measurements of the electronic heat capacity of graphene. It is enabled by combining a radio frequency Johnson noise thermometer, which can measure the electronic temperature with a sensitivity of ∼20 mK/Hz^{1/2}, and a photomixed optical heater that modulates T_{e} with a frequency of up to Ω = 0.2 THz. This allows record sensitive measurements of the electronic heat capacity C_{e} < 10 ^{–19} J/K and the fastest measurement of electronic thermal relaxation time τ_{e} < 10 ^{–12} s yet achieved by a calorimeter. These features advance heat capacity metrology into the realm of nanoscale and lowdimensional systems and provide an avenue for the investigation of their thermodynamic quantities. 

T00.00119: Characterization of niobium films with varying RRR values at low temperatures. Grigory Eremeev, Bektur Abdisatarov, Mustafa Bal, Hani E ElsayedAli, Akshay A Murthy, ZuHawn Sung, AnneMarie ValenteFeliciano, Anna Grassellino, Alexander Romanenko Niobium films are used both in microscopic superconducting qubits for quantum computing and in macroscopic SRF cavities for particle accelerators. Superconducting properties of niobium in microwave fields vary significantly with lattice defects and impurity content, where subat.% impurity level can reduce or increase microwave surface resistance by an order of magnitude. We studied the microwave properties of niobium films, deposited by different physical vapor deposition techniques, at low microwave fields correlating microwave properties at dilution fridge temperatures with material properties characterized with surface science techniques. 

T00.00120: Cyclotron resonance and measurements of the hole mass in La_{2x}Sr_{x}CuO_{4 }films Peter N Armitage, Anaelle Legros, Scott A Crooker, Kirk W Post, Ivan Bozovic, Xi He, John Singleton, Ross MacDonald Using timedomain terahertz spectroscopy in pulsed magnetic fields up to 31 T, we measure the terahertz optical conductivity over a broad doping range of cuprate La_{2x}Sr_{x}CuO_{4 }thin films. We observe systematic changes in the circularly polarized complex optical conductivity that are consistent with cyclotron absorption of ptype charge carriers. We have measured the cyclotron mass and field dependent changes to the scattering rates over a broad doping. We connect our observations to extant theory of the normal state electronic structure of these compounds. 

T00.00121: Nb_{3}Sn Coating of Complex Accelerator Cavity Structures Jayendrika K Tiskumara, Grigory Eremeev, Uttar Pudasaini, Jean R Delayen In the accelerator science field, most of the superconducting accelerator cavities are currently made out of niobium. Cavities coated with superconducting thin films with the potential to reduce the cost and improve the cavity performance are essential to the modern Superconducting Radio Frequency (SRF) accelerator research. Within the potential superconducting thin film materials, Nb_{3}Sn with its higher critical temperature and superheating field (both twice that of Nb) promises superior performance, notable cost reduction, and higher operating temperatures than Nb. The Sn vapor diffusion method is the most successful technique so far to coat niobium cavities with Nb_{3}Sn. Although there are several basic cavity models coated with Nb3Sn and tested at their specific frequencies, there is limited coating experience with complex cavity geometries to investigate Nb_{3}Sn potential for accelerator applications. This paper discusses recent progress made on the Nb_{3}Sn coating of the twin axis cavity at Jefferson Lab. This cavity with relatively complex geometry is proposed for energy recovery linac applications and will be helpful with measuring the superconducting properties of the Nb_{3}Sn. 

T00.00122: Room Temperature AntiStokes Shifted Superfluorescence Shuang F Lim, Kory Green, Kai Huang, Hans D Hallen, Gang Han Superfluorescence (SF) is a unique optical phenomenon that consists of an ensemble of emitters coupling collectively to produce a short but extremely intense burst of light. SF has also only been realized in extreme conditions (at low temperatures of around 6 K). Moreover, no antiStokes shift SF has been discovered in either an ensemble of nanoparticles or at bulky crystal levels. We report on a new lanthanidedoped upconversion nanoparticles (UCNPs) as a medium to achieve cavity free antiStokes shifted SF at room temperature, culminating in rapid, intense, and narrow spectral peaks of upconverted SF. This is the first time that SF has been discovered in a single nanocrystal regime and is the smallestever SF media. We observed the resultant UCNP SF with an extremely narrow spectral width at single nanocrystallevel (fullwidth at halfmaximum, FWHM = 2 nm), and to have a significantly shortened lifetime (τ = 46 ns, 10,000fold accelerated radiative decay, when compared to the lifetime of τ = 455.8 μs of normal upconversion luminescence (UCL). The significantly upspeeded upconverted SF lifetimes at tens of nanoseconds scale should break through the key limitation in normal UCL, and enable high speed bioimaging without compromising imaging quality. 

T00.00123: Scanning Atomic Absorption Spectroscopy Monitor for MBE Growth of Superlattices Gregory P Hainline, Ethan I Fenwick, Frank Tsui We report the construction of an atomic absorption spectroscopy (AAS) flux monitor capable of sequentially monitoring different elements through a single fiber optical pathway to control epitaxial growth of superlattices and other artificially structured materials. This capability is integrated into a 4channel (i.e., 4 fiber optical pathways) AAS monitor system and thus makes it possible to control in realtime codeposition of up to 4 elements and sequential deposition of more elements, including superlattices of 2 or more complex compounds, e.g., 2 ternary Heusler alloys. The AAS monitor works by transmitting light emitted by the same atomic species being deposited and measuring the absorbance of the light passing through the vapor, which has been calibrated and converted to atomic flux. Split mode fiber optics is used to combine the light beams from multiple atomic sources into one beam as it enters the vacuum chamber, while the absorbance is measured sequentially using a stepper motor driven monochromator via phase sensitive detection. The sensitivity and fidelity of the system is tested, including the comparison between the results from the new "scanning" version with multiple sources through one fiber optical pathway and those from the single sourcesingle channel monitor. 

T00.00124: Active control of surface phonon polariton resonance using a reconfigurable subwavelengththin nanostructure SATYANARAYANA R KACHIRAJU, Binod Paudel, Imtiaz Ahmad, Long Chang, Aiping Chen, MyoungHwan Kim Surface phonon polaritons (SPhP) have been considered as an alternative to plasmon polaritons due to low optical power loss in midinfrared. However, reconfigurable nanostructures are rarely achievable due to the lack of proper active materials suitable to polar dielectrics. We report numerical and experimental study of dynamic SPhP resonance control using a reconfigurable subwavelength nanostructure based on metalinsulator phase transition material, vanadium dioxide (VO2). We utilize a deeply subwavelengthscale VO2 nanocavity array on 6HSiC polar dielectrics which introduce both localized resonances and propagating cavity modes for SPhP. Both SPhP resonance frequencies rely on optical index of nanocavity which can be tuned by metalinsulator phase transition of VO2. We observe reflection spectrum under normal incidence of polarized light in Reststrahlen band of SiC (1012 microns wavelength) and temperature dependent resonance shift by heating up to 400 K. This work was performed, in part, at the Center for Integrated Nanotechnologies, an office of Science User Facility operated for the U. S. Department of Energy (DOE), Office of Science by Los Alamos National Laboratory (Contract 89233218CNA000001) and Sandia National Laboratories (Contract DENA0003525) 

T00.00125: Polaritonic and Excitonic Bose Einstein Condensates in a Periodic Potential Gabriel Pimenta Martins, Oleg L Berman, Godfrey A Gumbs We investigate two systems for BoseEinstein condensation. The first consists of excitons in a bilayer of twisted TMDC nanoribbons In the second case, we examine exciton polaritons, formed by excitons in a nanoribbon of TMDC, embedded in an optical microcavity, and microcavity photons. In both systems, BoseEinstein condensates (BECs) could be formed under periodic potentials. This periodic potential nay be caused either by the effective potential, acting on photons due to the special curvature of Bragg mirrors, or by the periodic potential, acting on excitons due to the Moiré sublattice in a twisted TMDC bilayer. We will calculate the limit of the pair correlation function for an infinitely long nanoribbon. We will analyze if it follows from this pair correlation function that the BEC in the nanoribbon subjected to the periodic potential exhibits features of the time crystal, caused by the behavior of the standing BEC wave, bounded in the transverse direction by the ribbon boundaries but unbounded along its length. 

T00.00126: Spin polarized nematic order, quantum valley Hall states, and field tunable topological transitions in twisted multilayer graphene systems Jianpeng Liu, Shihao Zhang We theoretically study the correlated insulator states, quantum anomalous Hall (QAH) states, and fieldinduced topological transitions between different correlated states in twisted multilayer graphene systems. Taking twisted bilayermonolayer graphene and twisted doublebilayer graphene as examples, we show that both systems stay in spin polarized, C3zbroken insulator states with zero Chern number at 1/2 filling of the flat bands under finite displacement fields. In some cases these spin polarized, nematic insulator states are in the quantum valley Hall phase by virtue of the nontrivial band topology of the systems. The spin polarized insulator state is quasidegenerate with the valley polarized state when only the dominant intravalley Coulomb interactions are included. Such quasidegeneracy can be split by atomic onsite interactions such that the spin polarized, nematic state become the unique ground state. Such a scenario applies to various twisted multilayer graphene systems at 1/2 filling, thus can be considered as a universal mechanism. Moreover, under vertical magnetic fields, the giant orbital Zeeman splittings in twisited multilayer graphene systems compete with the atomic Hubbard interactions, which can drive transitions from spin polarized zeroChernnumber states to valleypolarized QAH states with small onset magnetic fields. 

T00.00127: Electronic transport on 2D nanodevices under strong electromagnetic field Pablo H Rivera Riofano, F. Huaraya, A. A Perez, R. A Montalvo The electronic transport on nanodevices are well described by LandauerBüttiker approach. In these schema, we observe the quantization of conductance and his evolution depending on temperature where the electronic distribution function vary sensibly on the electronphonon interactions. 

T00.00128: Theoretical description of the Cyclotron Resonance in DualGated Bilayer Graphene Matheus O Schossler, Jordan Russell, Yafis Barlas, Alexander Seidel, Erik A Henriksen Recent experimental observations of cyclotron transitions involving the quasizero energy Landaulevel (LL) octet in dualgated graphene bilayer call for a theoretical description of the dependence on displacement (D) field. These transitions involve the positive and negative energy LLs above and below the octet indexed by N=2 and N=2, respectively. We present results treating Coulomb interactions within HartreeFock approximation both within the octet and the index N=2 LLs. For D=0, good qualitative agreement is achieved for transitions at filling factors ν varying from 6 to 6. At ν=0 and small D, we find a LL polarized phase driven by particlehole breaking terms where the 0th LL is below the Fermi energy, blocking 1→ 2 transitions. For intermediate D, a phase transition is predicted from this state to a layer polarized regime that is captured by the singleparticle description. At ν=4 , strong agreement is found between theory and experiment for the Ddependence of the 1→ 2 transitions. 

T00.00129: Floquet higher order topological insulator and superconductor Tanay Nag After exploring much on twodimensional higherorder topological superconductors (HOTSCs) hosting Majorana corner modes (MCMs) only, we propose a simple fermionic model based on a threedimensional topological insulator proximized with swave superconductor to realize Majorana hinge modes (MHMs) followed by MCMs under the application of appropriate WilsonDirac perturbations. We interestingly find that the secondorder topological superconductor, hosting MHMs, appears above a threshold value of the first type perturbation while the thirdorder topological superconducting phase, supporting MCMs, immediately arises incorporating infinitesimal perturbation of the second kind. Thus, a hierarchy of HOTSC phases can be realized in a single threedimensional model. Additionally, the application of bulk magnetic field is found to be instrumental in manipulating the number of MHMs, leaving the number for MCMs unaltered. We analytically understand these abovementioned numerical findings by resorting to the low energy model. We further characterize these topological phases with a distinct structure of the Wannier spectra. From the practical point of view, we manifest quantized transport signatures of these higherorder modes. Finally, we construct Floquet engineering to generate the hierarchy of HOTSC phases by kicking the same perturbations as considered in their static counterpart. We also investigate the hierarchy of Floquet higherorder topological insulator phase in three dimensions. 

T00.00130: Roomtemperature ferroelectricity and memory effects in a new van der Waals crystal Yinchang Ma, Xixiang Zhang, Chenhui Zhang Van der Waals (vdW) ferroelectric material has emerged as an essential part of modern highdensity electricfieldcontrolled information storage device due to its nonvolatile polarization accompanied by its weak van de Waals interlayer coupling which enables the separation of atomic thick fewlayer flakes from its bulk crystal. However, the number of vdW ferroelectric materials which show both roomtemperature 2D ferroelectricity and fewlayer air stability is still very small, mainly due to the increasing depolarization field and chemical activity in ultrathin flakes. Here, we report a new vdW ferroelectric crystal, which persists its ferroelectricity down to monolayer at room temperature. Ferroelectric multidomain phase is achieved by applying a tipinduced electric field on the flakes with a thickness down to 4 nm. Strikingly, the ferroelectricparaelectric phase transition was observed at around 200°C via a combination of temperaturedependent piezoresponse force microscope (PFM) measurement and dielectric constant measurement, indicating that its polarization is able to persist at a higher temperature compared with most existing vdW ferroelectric materials. Firstprinciple calculation was adopted to explain the origin of the ferroelectric dipoles. Moreover, a vertical ferroelectric diode was built up, showing its 2D ferroelectricity in an approach of electric transport measurement, and also acts as a prototype of the nonvolatile memory device. This finding reveals this new vdW ferroelectric crystal has the capability to be integrated with other existing 2D materials into functional heterostructure and also designates it as a promising candidate for nextgeneration information storage nanodevices. 

T00.00131: Effects of disorder in vortexbound Majorana states in ironbased superconductors Zhibo Ren, Jukka Vayrynen Majorana zero modes have been predicted to be hosted by vortices in the surface of a topological superconductor. Recent prediction of a family of ironbased superconductors as a topological material, and the subsequent observations of zerobias conductance peaks in vortex cores of such materials, have sparked interest in vortexbound Majorana states. We study numerically vortices in ironbased superconductors in the topological phase. In the presence of a single vortex, we study the effects of surface and bulk disorder on the vortex subgap spectrum. The calculated spectra can be measured in STM experiments. We also consider thin films where the top and bottom surfaces are coupled. We then consider the coupling between two nearby vortices and calculate the hybridization energy of the two Majorana states. 

T00.00132: Giant magnetoconductivity in noncentrosymmetric superconductors Michael Smith, Anton V Andreev, Boris Spivak We discuss a novel physical mechanism which gives rise to a giant magnetoconductivity in noncentrosymmetric superconducting films. This mechanism is caused by a combination of spinorbit interaction and inversion symmetry breaking in the system, and arises in the presence of an inplane magnetic field H. It produces a contribution to the conductivity, which displays a strong dependence on the angle between the electric field E and H, and is proportional to the inelastic relaxation time of quasiparticles. Since in typical situations the latter is much larger than the elastic one this contribution can be much larger than the conventional conductivity thus leading to giant microwave absorption. 

T00.00133: NIR/MIR Induced Ultrafast CarrierDynamics in Graphene Sachin Sharma, Edward Sanchez, Rachael L MyersWard, Matthew DeJarld, Kurt D Gaskill, Paola Barbara, Stephen B Cronin, Ioannis Chatzakis We are reporting on ultrafast carrier dynamics in quasifreestanding bilayer and monolayer graphene using MIRpump, THzprobe pulses. A wide range of mid IR wavelengths were used for the excitation of the sample and the subsequent carrierrelaxation dynamics has been monitored by THz pulses. We observed a large variation in the carrier relaxation time t indicating a strong dependence on the mid IR excitation wavelength of the excitation pulses. It is well established that after the excitation of the graphene, the electron gas is internally thermalized in about 200 to 300 femtosecond via Coulomb interactions. Subsequently, carrier relaxation occurs via electronlattice cooling involving the strongly coupled optical and acoustic phonons. Multiple theoretical and experimental studies suggest shorter decay time for photoexcitation energies E_{n} larger than the stronglycoupled optical phonon energy (E_{phonon}~200 meV). However, up to an order of magnitude longer decay times have been reported for E_{n} < 2E_{F}, where E_{F }is the Fermi energy. We report on much longer decaytimes for a range of excitation energies, where E_{n} > 2E_{F}. Consequently, our measurements do not fully support these observations and further investigations are ongoing to understand the underlying phenomenon. 

T00.00134: Evolution of multipartite system in thermal environment Alwin van Steensel, Mohammad H Ansari We study the evolution of a multipartite system with weak couplings to a number of thermal reservoirs. We additionally apply external drives to manipulate the system thereby adding a means to control its evolution. Such a setup can be of interest in quantum computation where heat produced in the processor can lead to temperature gradients, affecting gate fidelities. In such systems the control drives can be used to optimise quantum processor performance. 
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T00.00135: Negative critical current in superconductor1D metalsuperconductor Josephson Junctions Tony Liu, Boris Spivak, Anton Andreev, Alexander V Razhkov We study the Joshepson effect in superconductor1D metalsuperconductor junctions. In the presence of Coulomb interaction, the number of electrons in the normal metal part of the SNS junction is controlled by the voltage on the gate. We show that the sign of the critical current alternates as a function of the number of electrons in the 1D normal region. For an odd number of electrons the πcontact is realized. The alternation of the sign of the critical current can be traced to the node theorem for onedimensional wave functions. 

T00.00136: Recent advances on coherent perfect absorberlaser systems Mohamed Farhat, PaiYen Chen, Sebastien Guenneau, Ying Wu We present recent advances in the field of coherent perfectabsorber and laser (CPAL) for different kinds of waves. We show that this intriguing effect is enabled by paritytime symmetry breaking. We first report a monochromatic electromagnetic sensor with unprecedented sensitivity. Different from exceptional pointbased concept, the sensor operates via the selfdual spectral singularity of CPAL. This scheme may thus detect small perturbation including lowdensity gas molecules. We implement the twoport transmission line model to study its performance and a FabryPerot interferometric sensor will be chosen for comparison. As the sensing scheme does not rely on frequency swept measurement, it can have no limitations due to noise. 

T00.00137: Mechanics of Hybrid Square Lattices with Tunable Thermal Expansion Coefficient Siyao Liu, Yaning Li New hybrid square lattices are designed, which are composed of hard cells or inclusions connected via specially designed soft components, such as soft networks, soft hinges, or bilayer joints. Upon external stimuli, the curvature of the joints will change due to the stimuliinduced mismatch. Also, the square cells will rotate due to the chiral arrangement of the cells connected by the stimuliresponsive joints. Both deformation mechanisms will contribute to the overall volume change of the material and lead to the change in both mechanical properties and functionality related to the material structure. To further prove the concept, prototypes of selected designs are fabricated via a multimaterial 3D printer. Uniaxial tension experiments are performed in a thermal chamber. By varying the temperature, due to the mismatch in thermal expansion of the bilayer and the chiral design of the hybrid square lattices, the material experiences dramatic volume change. By varying the design parameters, including material combination and geometry, both overall positive and negative thermal expansion coefficients can be achieved. The mechanical property, structure, temperature relationships are quantified. In addition, numerical simulations are performed to support mechanical experiments. 

T00.00138: Dynamic control of excitons in singlelayer WSe_{2} with surface acoustic waves Sheikh Parvez, Samuel Berweger, Nicholas Borys Singlelayer (1L) WSe_{2} exhibits narrow optical emission at low temperatures from a large suite of excitons, which are the dominant excited states in the 2D semiconductor. Excitons in 1LWSe_{2} can be controlled via localized strain which creates a quantum well for the excitons. The goal of this project is to dynamically manipulate excitonic properties in 1LWSe_{2} with surface acoustic wave (SAW) excitations. SAWs can be used to control and create regions of localized tensile strain and thus promise the ability to electronically control key exciton properties such as their energies and lifetimes. Our recent results have demonstrated the successful fabrication of a 1LWSe_{2}/hexagonal boron nitride 2D heterostructure on a SAW device. The heterostructure configuration maintains the bright excitonic emission of the 1LWSe_{2} and exhibits highquality excitonic phenomena. Ongoing fabrication efforts are focused on establishing microwave connectivity to the hybrid 2D materialSAW device to characterize how SAWs affect the exciton complexes and associated phenomena in 1LWSe_{2} with the overall goal of identifying new opportunities for controllable optoelectronic and photonic quantum devices. 

T00.00139: Optimization of Molecular Beam Epitaxial Growth of thin films of a threedimensional Dirac semimetal Nicholas R David, Dana Peirce, Payton Downey, Simranjeet Singh, Jyoti Katoch Three dimensional topological Dirac semimetals (TDS) such as Na3Bi, have attracted great attention in condensed matter physics due to their rich physics and possible revolutionary technological applications. Confining Na3Bi to the ultrathin regime opens a bulk bandgap and has shown to exhibit the quantum spin Hall effect. We will show our results on the high quality epitaxial thin film growth of Na3Bi on a magnetic insulator using molecular beam epitaxy (MBE) technique. We will discuss and compare our result on the epitaxial growth of Na3Bi using two different growth techniques, i.e., flux matched codeposition and alternating layer by layer growth. The highquality crystallinity of the Na3Bi films is monitored using insitu reflection high energy electron diffraction (RHEED). The MBE grown films are further characterized (charge carrier density and charge carrier mobility) via insitu magnetotransport measurements in an ultrahigh vacuum environment. 

T00.00140: Unconventional Flat Chern Bands and Preformed 2e Charges in Skyrmionic Moiré Superlattices Yifei Guan, Alexander Kruchkov, Oleg V Yazyev The interplay of topological characteristics in real space and reciprocal space can lead to the emergence of unconventional topological phases. In this talk, we implement a novel mechanism for generating higherChern flat bands on the basis of twisted bilayer graphene (TBG) coupled to topological magnetic structures in the form of the skyrmion lattice. In particular, we discover a scenario for generating C = 2 dispersionless electronic bands when the skyrmion periodicity and the moir ́e periodicity are matched. Following the Wilczek argument, the statistics of the chargecarrying excitations in this case is bosonic, characterized by electronic charge Q = 2e, that is even in units of electron charge e. The required skyrmion coupling strength triggering the topological phase transition is realistic, with its threshold estimated as low as 4 meV. The Hofstadter butterfly spectrum of this phase is different resulting in an unexpected quantum Hall conductance sequence. 

T00.00141: Uncertainty Relations for Mesoscopic Coherent Light Eric Akkermans Thermodynamic uncertainty relations unveil useful connections between fluctuations in thermal systems and entropy production. This letter extends these ideas to the disparate field of zero temperature quantum mesoscopic physics where fluctuations are due to coherent effects and entropy production is replaced by a cost function defined using a novel disorder reversal operator. A simple expression is obtained for the average cost function, which depends on the dimensionless conductance g and on a geometrical factor B controlled by boundary conditions. Contrary to thermodynamic machines aimed at minimising fluctuations to increase precision, it is desirable in mesoscopic devices to increase coherent effects. The cost function indicates that increasing coherent effects can be achieved by playing with the geometry and boundary conditions through B and not only by decreasing the bulk conductance g. 

T00.00142: Zero Modes in Bipartite Lattices: Vacancies, Boundary Conditions and Disorder Eric Akkermans We study bipartite lattices with vacancies (specifically graphene) and zero modes. Bipartite lattices are defined as direct sums of two sublattices A and B so that each site is connected only to sites of the other sublattice. The spectrum of single particle Hamiltonians on such lattices hosts at least NA−NB zero modes where NA (NB) is the number of sites on sublattice A (B). A vacancy defined by the removal of a single site, can be either of type Aor B. Creating vacancies in a bipartite lattice changes the imbalance NA−NB and therefore changes the number of zeromodes. Such zero modes in graphene are topological in nature and are spatially localized on the vacancy sites. We study the effects of boundary conditions and disorder on the appearance of these zero modes and their corresponding wave functions. 

T00.00143: Systematic analysis of topological and magnetic propertiesof materials related to MnBi_{2}Te_{4} by substitution Caelia M Thomas, Kevin F Garrity, Francesca Tavazza, Sugata Chowdhury The search for materials with axion insulator phases has motivated extensive research about interactions between topological surface states and symmetrybreaking magnetic ordering, with possible applications in spintronics and quantum information. Recently, experimental and theoretical works have focused on MnBi_{2}Te_{4 }(MBT), which is predicted to display the exotic quantum phase. In this work, we have looked MBT family (MnB_{2}X_{4} (B = Sb, Bi; X=Se, Te)). We study the topological properties and magnetic properties of new candidate materials. Our calculations reveal several potential topological materials, with properties depending on the filling of d electrons and the magnetic ordering. We demonstrated that the topological phase transition completely depends on the chemical composition of the materials. These types of stoichiometric magnetic materials are an excellent candidate for future topological devices. 

T00.00144: Timereversal symmetry breaking and multigap superconductivity in the noncentrosymmetric superconductor, La_{7}Ni_{3} Arushi . Unconventional superconductors are the most studied classes of materials and are still an active area of research in condensed matter physics. Noncentrosymmetric superconductors (NCS) are the one particular class that exhibit unconventional superconducting features and the spontaneous breaking of an additional symmetry known as the timereversal symmetry (TRS). In NCS, the antisymmetric spinorbit coupling (ASOC) leads to the admixture of spinsinglet and triplet components and is also proposed to be related to the broken TRS. However, the recent observation on these systems opens up questions on the correlation of the broken TRS with ASOC and requires further research to conclude the mechanism inducing unconventional ground state. 

T00.00145: A Combined First Principles Study of the Structural, Magnetic, and Phonon Properties of Monolayer CrI_{3} Brenda M Rubenstein, Daniel Staros, Guoxiang Hu, Juha Tiihonen, Ravindra Nanguneri, Jaron Krogel, M. Chandler Bennett, Olle Heinonen, Panchapakesan Ganesh In recent years, 2D materials have garnered a wealth of interest because of their unique lowdimensional physics, exotic magnetism, and the relative ease with which their properties can be tuned via doping, crinkling, strain, and stacking. The first magnetic 2D material to be discovered, monolayer (ML) CrI_{3}, is particularly fascinating due to its ground state ferromagnetism, which can be employed to design spintronic materials. Yet, because monolayer materials are notoriously difficult to probe experimentally, much remains unresolved about CrI_{3}’s properties. Here, we report predictions of the atomic magnetic moments, lattice parameters, and geometry of ML CrI_{3} using highly accurate fixednode Diffusion Monte Carlo (DMC) calculations. Alongside Density Functional Theory (DFT) benchmarked by DMC, we also predict its spinphonon/lattice couplings. Notably, we find that the atomic magnetic moments in CrI_{3} are 3.62 μB per chromium and 0.145 μB per iodine, which are both quite large, supporting a potentially large ligand superexchangedominated magnetic anisotropy. Our DMCpredicted lattice constant (a_{0}) of 6.87 Å is also very close to the experimental a_{0} = 6.84 Å, demonstrating the predictive power of DMC for geometry and magnetism in 2D materials. 

T00.00146: Effect of applying electric field on the absorption coefficient in GaAs/Al_{x}Ga_{1x}As layered coreshell spherical quantum dots Gabriel Rodriguez Guijarro, Juan Carlos Martinez Orozco, Karla A Rodríguez Magdaleno Nowadays the study of semiconductor nanostructures has gained importance since they have a wide range of optoelectronic applications. Quantum dots, a branch of these systems, receive great attention due to their trend to emit in the terahertz region of the electromagnetic spectrum. This work presents the linear optical properties of a GaAs/Al_{x}Ga_{1x}As layered core shell spherical quantum dot, particularly the intraband absorption coefficient changing as a function of intrinsic properties such as the width and aluminum concentration of the shells and we also consider the effect of applying an electric field as well as hydrostatic pressure. The electronic structure was calculated using the finite element method to solve the system’s Schrödinger equation. It was found that the main optical transition is between the 1s and 1p electronic states. The study shows that the absorption coefficient has different behaviors depending on the composition of the quantum dot and that it can be tuned by controlling external factors such as electric field and hydrostatic pressure. 

T00.00147: Effect of H2S orientation on its dissociation on Fe(110) surface Omotayo a Salawu, El Tayeb Bentria, Fedwa El mellouhi, Othmane Bouhali Over the years, there has been interest in the design of efficient system that inhibits corrosion on metallic surfaces. This is because the deterioration of the metals, socalled metal dusting incurs great cost to the economy. This process involves the transfer of carbon into solid solution saturating the metal phase in the process. When this occurs, cementite forms at the surface and serves as barrier to the diffusion of the carbon into the metal surface. One way proposed to tackle this is the addition of Sulfurbased compound, for instance H2S to the environment where these reactions take place.The presence of H2S in this environment allows the adsorption of sulfur on the Fe surface.This leads to the retardation of the transfer of C as the adsorbed sulfur blocks the reaction sites. In order to effectively utilize this approach, it is important to understand the kinetics of the retarding procedure.We present density functional theory calculations on the role of orientation of H2S molecule on its adsorption and dissociation on Fe (110) surface.Our investigation considered different concentration of H2S: high (0.25ML) and low (0.0625ML) respectively. We report the geometries and energetics for an exhaustive set of adsorption and decomposition states induced by H2S molecule on the considered coverages. We find that H2S can be either adsorbed as a molecule or as HS+H depending on the orientation of the molecule and the site of adsorption. Molecular H2S was found to adsorb weakly on either the long or short bridge sites which are potential reaction sites for the carburization.Our findings show that the orientation of H2S play significant role in determining the elementary pathways to its dissociation on Fe (110) surface. 

T00.00148: Interface and Bending Effects on Ferroelectricity in Ultrathin CuInP_{2}S_{6} Probed by Piezoresponse Force Microscopy Yongtao Liu, Shaoqing Ding, Jinyuan Yao, Justin R Rodriguez, Yanglin Zhu, Zhiqiang Mao, Eugene A. Eliseev, Anna N. Morozovska, Ying Liu, Sergei V. Kalinin Van der Waals (vdW) ferroelectrics have attracted intense interest recently due to their potential in realizing ferroelectricity in the ultrathin limit. When the thickness of a ferroelectric vdW material becomes very thin, the competition between depolarization field, surface chemistry, and bending strain will affect the electric polarization. In addition, chemistry at the interface between the vdW material and the electrode may also modify the ferroelectric properties. In this work, we investigate the ferroelectric domains of in nanoflakes of CuInP2S6 (CIPS), a vdW material that is ferroelectric at room temperature, focusing on the effect of surface and interface conditions, as well as the vdW layer bending curvature. A vdW CIPS nanoflake is layer transferred onto monolayer graphene which is in turn placed on a SiO_{2}/Si substrate. To investigate the effect of electrodes on the ferroelectricity of CIPS, we also prepared a Pt electrode on the CIPS nanoflake. We performed band excitation piezoresponse force microscopy to visualize the ferroelectric domain structures and band excitation piezoresponse spectroscopy to investigate the polarization switching dynamics. We observed a large effect of the interface and the layer bending curvature on the domain structure and polarization of CIPS flakes. The importance of the interface and layer bending curvature will be explored both experimentally and theoretically. 

T00.00149: Reconstruction of lowindex Au surfaces using largescale machine learning molecular dynamicswith manybody Bayesian force fields Cameron J Owen, Lixin Sun, Yu Xie, Boris Kozinsky Gold surfaces have a long history of microscopic studies due to their propensity to reconstruct in complex patterns depending on the terminating surface facet and the environment (temperatures and atmosphere). However, the details of restructuring processes and metastable intermediate structures, which could be critical for catalytic reactions, remain unknown due to the limits of microscopy time resolution and accuracy of classical force field simulations. 

T00.00150: Metalinsulator transition in LaVO_{3} thin films Nathan Bairen, James A Payne, Dakota T Brown, Maitri P Warusawithana Using Molecular Beam Epitaxy (MBE), we grew thin films of LaVO_{3} under a partial pressure of oxygen and ozone of ~1∙10^{7} torr and a substrate temperature of ~650° C. To probe the electrical properties of the material, we applied a bipolar current across the samples over a range of temperatures, taking the average of the voltages produced by currents in either direction to determine the resistivity. The samples showed metallic transport down to near 120 K, with the resistivity decreasing by a factor of 20 compared to that at 300 K. Below 120 K, a drastic change in the electronic properties of the samples appears, suggestive of a transition to a gapped state. 

T00.00151: Electronic Structure of Strongly Correlated felectron Rareearth Metals Using Density Functional Theory and Dynamical Mean Field Theory Vijay R Singh, Uthpala K Herath, Benny Wah, Aldo H Romero Rareearth (RE) elements are found in a wide range of functional materials with diverse applications. The localized f orbitals of the RE element play a crucial role in determining electronic correlations. However, the computational material design of such strongly correlated materials is challenging in modern condensed matter physics since it requires the development of more accurate methodologies beyond density functional theory (DFT). The main issue in the felectron system is the understanding of the localizationdelocalization transition occurring on different RE materials. The present talk will discuss dynamical meanfield theory (DMFT) combined with DFT electronic structure of strongly correlated felectron RE metals such as Sm (4f^{6}), Gd (4f^{7}) and Dy (4f^{10}). Here, I use the DMFT+DFT method implemented using the maximally localized Wannier function as the local basis set and combining various DFT codes to study the electronic properties of these materials. Our results will also be compared to other DMFT+DFT codes employing different local basis sets and DFT implementations. 

T00.00152: Midinfrared anomalous Hall measurement in PrAlGe magnetic Weyl semimetal Yejin Kwon, Bryan Valdes, Keunki Cho, Beoungki Cho, MyoungHwan Kim Weyl semimetals have a quasiparticle excitation called Weyl fermions, which appear in a material with two nondegenerate bands crossing near Fermi level in threedimensional momentum space. Lowenergy excitation at two band crossing points is called Weyl points. The pairs of Weyl points produce a large Berry curvature contributing to the intrinsic anomalous Hall conductivity. Here, we report midinfrared anomalous Hall conductivity in PrAlGe magnetic Weyl semimetal in proximity to the Fermi level at 70 meV – 200 meV with applying magnetic field below 1T and temperatures of 4 K – 300 K. PrAlGe shows ferromagnetic ordering below 0.4T at below 15 K. The magnetic Weyl semimetals show the magnetic field control of the Weyl point positions in momentum space emerging large intrinsic anomalous Hall conductivity at lowenergy band below 100 meV. We develop custombuilt broadband magnetooptical spectroscopy system at midinfrared spectral range which utilizes a double modulation from a Fouriertransform infrared spectrometer and photoelastic modulator. Polarization rotation and ellipticity angle spectrums of PrAlGe in Kerr geometry are measured. We convert Kerr angle to Hall angle by using optical conductivity obtained from reflection spectrum measurement with KramersKronig analysis. 

T00.00153: Band Structure and Polarization Effects in Photothermoelectric Spectroscopy of a Bi_{2}Se_{3} Device Seyyedesadaf Pournia, Giriraj Jnawali, Howard E Jackson, Ryan F Need, Stephen D Wilson Bi_{2}Se_{3} is a prototypical topological insulator which has a small band gap (~0.3 eV) and topologically protected conducting surface states. Here we show in a quasibulk nanoflake device that we can measure the energy dependent optical absorption through the photothermoelectric effect. Spectral signatures are seen for several optical transitions between the valence and conduction bands, as well as the 1.5 eV optical transition between the two topologically protected conducting surface states. We also observe a surprising linear polarization dependence in the response of the device which reflects the influence of the metal contacts. 

T00.00154: Interaction corrections to thermopower in the twodimensional electron gas Zahidul Islam Jitu, Georg Schwiete We study how electronelectron interactions enhance or suppress the Seebeck coefficient in the disordered electron gas at low temperatures. We performed a detailed perturbative calculation of the heat densitydensity correlation function for shortrange and longrange Columb interactions. For longrange interactions, we found logarithmic corrections from the subtemperature intervals of energies in addition to AltshulerAronov corrections. In this poster presentation, I will discuss how these logarithmic corrections fit into the structure of the correlation function. 

T00.00155: Midinfrared thermal emission from coupled surface plasmonphonon polariton resonances Imtiaz Ahmad, Satya Kachiraju, Michael Totedo, Ivan Nekrashevich, Long Chang, MyoungHwan Kim Strong coupling of infrared light and surface polarized ions provides a unique channel between photon and phonon via electric charge oscillations, which enables bidirectional energy flow between optical and thermal energy. Therefore, optical metasurfaces based on phonon polaritons are promising candidate as thermal metasurfaces according to Kirchhoff’s law of thermal radiation stating that the absorptivity of a resonator is equal to the emissivity. For a synchronized emission, resonators have crosstalk each other. We observe a welldefined and narrowband thermal emission from coupled surface plasmonphonon polariton resonance induced by deeply subwavelengthscale resonant nanocavity arrays. Metal (gold)insulator (silicon) layered nanocavity on polar dielectric crystal (silicon carbide) confines a guided mode of coupled surface plasmonphonon polaritons with halfwave FabryPerot resonance condition. Each cavity has a crosstalk with near neighbor cavities. We develop a midinfrared grating spectrometer integrated into infrared microscope with Fourier transform infrared spectrometer. The filtered thermal emission by two spectrometers is observed while heating the sample up to 400 K. Our thermal emitter platform will benefit to design thermal metasurfaces. 

T00.00156: Exfoliation and Characterization of 2D Materials Pooja Chopra, Parveen Kumar The monolayers as thin as a single layer of atoms of 2D materials have demonstrated distinctive electronic, optical, and catalytic properties. These 2D semiconductors with different bandgap energies can be put together to form a heterojunction to tune the properties of the material for different optoelectronics applications. This study focuses on the exfoliation of various 2D materials using the noble idea of mechanical exfoliation by scotch tape. The monolayers of exfoliated materials are investigated using optical and electrical characterization techniques. Finally, physical modification strategies are demonstrated to effectively tune the intrinsic electronic structures for various optoelectronic applications. 

T00.00157: Optical signature of alternating domains with outofplane electric polarization in twisted transition metal dichalcogenide Yinong Zhang Twisting twodimensional materials with a small twist angle leads to a plethora of rich physical correlated and topological phenomena. Yet another emergent example is alternating domains with outofplane electric polarization in twisted hexagonal boron nitride and transition metal dichalcogenides systems. In this work, we perform optical spectroscopy of twisted double bilayers of transition metal dichalcogenides and reveal rich optical response, which could be further controlled by an outofplane electric field from a dual gate geometry. Our results demonstrate the delicate coupling between the excitonic response and the moire electric polarization, which is further visualized through scanning probe techniques. 

T00.00158: A firstprinciples based microkinetic simulation of the role of sulfur in controlling surface chemistry of CO reactions on Fe surface Omotayo a Salawu, El tayeb Bentria, Fadwa El mellouhi, Othmane Bouhali 

T00.00159: Aspects of topological superconductivity in SnTaS_{2} Mainpal Singh, Pallavi Saha, Vipin Nagpal, Satyabrata Patnaik Topological superconductivity has attracted considerable attention in the recent past with the promise of potential applications in quantum computation. Layered dichalcogenides in particular have provided the platform to explore such nuanced features. We have recently reported evidence for topological superconductivity in Sr intercalated Bi_{2}Se_{3} . In the present study we shall discuss synthesis and characterization of nodal line semimetal SnTaS_{2}. Measurements on our as grown single crystals of SnTaS_{2} shows superconductivity below T_{c} ̴3K. High quality single crystals (RRR ~ 500) were prepared using chemical vapor transport method. The temperature dependent resistivity shows linear behavior at higher temperatures, confirming the dominance of electron phonon scattering mechanism. The magnetization studies support the material to be a type II superconductor. The anisotropy in upper critical magnetic field (Hc_{2}) is clearly observed in resistivity plots in two different orientations of single crystal. In particular, we would compare the characteristics of SnTaS_{2} vis a vis Sr_{x}Bi_{2}Se_{3 }, specifically on the aspects of topological superconductivity. 

T00.00160: Effect of oxygenation on adsorption properties of pristine FePc and F_{16}FePc on Ru(0001) surface: DFT study Abdelkader Kara, meysoun jabrane, mohamed el hafidi, Moulay Youssef El hafidi In this work, we study the effect of oxygenation of Ru(0001) surface on the adsorption properties of FePc and F_{16}FePc by exploiting density of functional theory calculations and taking into consideration the van der Waals interaction, optB88 functional specifically. We compare the results between the pristine surface and O(2X2)/Ru(0001). The magnetic moment of the molecules adsorbed on pristine Ru(0001) is partially quenched but is enhanced when the molecules are adsorbed of O(2X2)/Ru(0001). Initially, the clean Ru(0001) loses charge to molecules, however the substrate gains charge from the molecule in the case of oxygenated system which leads to oxygentuned electronic properties for electronics applications. 

T00.00161: Utilizing Density Functional Theory to Study the Carbon Dioxide Reduction Reaction on Variants of Monolayer MoSSe Brenna Turnbull, Gracie Chaney Throughout the past decade, twodimensional transition metal dichalcogenides (2D TMDs) have been 

T00.00162: Experimental and computational study of thermallydriven phase separation of mixed thiol SAMs on Au(111) Jarrod E Schiffbauer, Clark M Willis, Josh T Burget, Marygrace M Prinster, Matthew B Wilson Mixed selfassembled monolayers with two or more distinct components and have been shown experimentally to undergo phase separation. Control over phase separation and composition of mixed monolayers would allow one to “tune” the properties of the surface, like thermal conductivity, wetting/capillary behavior, or interactions with complex molecules like proteins. The present reseracrh concerns whether it is possible to modulate domain morphology and composition by varying the cooling rates during SAM formation. Both experiments and simulations of phase separation are carried out. This synergy will allow us to reduce the number of experiments necessary to control over the domain formation of the SAMs. Through AFM characterization, we have seen experimentally that there is a correlation between SAM domain size, morphology, and the rate of cooling. We also have developed a numerical model that introduces temperature dependence into the CahnHilliard equation to model domain formation of SAMs with a decaying temperature. Here we present and compare current simulations and experiments. 

T00.00163: Exact Quadratic Effective Hamiltonian for the Hubbard Model and its Exact Solutions Xindong Wang, Xiao Chen, Liqin Ke, HaiPing Cheng, Bruce Harmon

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T00.00164: NonAbelian Tensor Berry Connections in Multiband Topological Systems Giandomenico Palumbo In this talk, we introduce and apply nonAbelian tensor Berry connections to topological phases in multiband systems. These gauge connections behave as nonAbelian antisymmetric tensor gauge fields in momentum space and naturally generalize Abelian tensor Berry connections and ordinary nonAbelian (vector) Berry connections. We build these novel gauge fields from momentumspace Higgs fields, which emerge from the degenerate band structure of multiband models. First, we show that the conventional topological invariants of twodimensional topological insulators and threedimensional Dirac semimetals can be derived from the winding number associated with the Higgs field. Second, through the nonAbelian tensor Berry connections we construct higherdimensional BerryZak phases and show their role in the topological characterization of several gapped and gapless systems, ranging from twodimensional Euler insulators to fourdimensional Dirac semimetals. Importantly, through our new theoretical formalism, we identify and characterize a novel class of models that support spacetime inversion and chiral symmetries. Our work provides a unifying framework for different multiband topological systems and sheds new light on the emergence of nonAbelian gauge fields in condensed matter physics, with direct implications on the search for novel topological phases in solidstate and synthetic systems. 

T00.00165: Development and Testing of the Scanning Majorana Microscope Elinore L McLain, Kaedon ClelandHost, Eric W Goodwin, Michael Gottschalk, Stuart H Tessmer Majorana states in condensed matter systems have the potential to impact qubit technology for nextgeneration topological quantum computers. Protected by topology and particlehole symmetry, Majoranas are insensitive to local perturbations, unlike typical qubit architectures. The Scanning Majorana Microscope is a novel technique developed to detect a unique signature of Majorana zero modes. The microscope uses a sensitive chargesensing circuit to count individual electrons entering a metallic quantum dot on the tip of a glass scanning probe. This poster will present two key milestones that have been accomplished. The first is a demonstration of the probe's capability to count single electrons. The second milestone is confirmation that the probe can adequately perform the basic functions of a scanning tunneling microscopy tip. This includes approaching safely to within tunneling range of the sample. This capability allows for us to hybridize the quantum dot electron wavefunctions at the apex of the tip with candidate Majorana states in the sample. 

T00.00166: DFT+DMFT Study of the lattice disorder effect due to molecular conformations in a bandwidth controlled Mott insulating organic material Hyowon Park κ(BEDTTTF)_{2}X organic is a wellknown typical Mott insulator in which the metalinsulator transition is driven by the narrow electronic bandwidth between molecular orbitals. Here, we study the lattice disorder effect from subtle molecular conformations due to the rotation of molecular orbitals on electronic structure of this strongly organic material using density functional plus dynamical mean field theory. Near the metalinsulator transition boundary, the organic structure with the homogeneous eclipsed conformation exhibits a Fermiliquid metallic state while the samevolume structure with the homogeneous staggered conformation becomes a Mott insulator. Remarkably, the inhomogeneous configuration of both eclipsed and staggered conformations can also induce the Mott insulating state since the electronic bandwidth is much reduced than that of the homogeneous eclipsed one while the energy of the inhomogeneous phase is lower than that of the Mott insulating staggered structure. Our results show that the lattice disorder effect due to inhomogeneous molecular conformations can play an important role to the study of the Mott transition in this and related correlated organic materials. 
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T00.00167: Atomiclevel compositions, structures, and surface properties of nitrogenfunctionalized nanoporous carbons Bradley F Chmelka, Shona Becwar, Niels P Zussblatt, Ziyang Wei, Nina Fechler, Rongli Liu, Xiangfeng Duan, Philippe Sautet Nanoporous nitrogenfunctionalized carbon materials exhibit a combination of desirable properties that include high N contents, high fractions of N moieties at surface sites, 3nm pores to promote diffusion, and electron conductivity to surface N environments where reactions occur. Such properties have been challenging to understand and control, due to the materials’ nonstoichiometric compositions, high electrical conductivities, heterogeneous surfaces, and complicated structural order and disorder that have important influences on their transport, adsorption, and reaction behaviors. Nevertheless, nanoporous Ncarbons can be probed over multiple length scales by using 2D NMR spectroscopy, Xray scattering, and DFT modeling, to correlate insights on local bonding environments and interactions with macroscopic material properties. Interestingly, the types, quantities, and distributions of Nheteroatom environments, notably those at surface sites, depend strongly on the composition and physical properties of the nanoporegenerating template used. The analyses correlate the atomicscale compositions, nanoscale structures, and macroscopic O_{2} and sulfur reduction properties of nanoporous Ncarbons as promising nonpreciousmetal cathode electrocatalysts for fuel cells and batteries. 

T00.00168: Fabrication of embedded plasmonic antennas for nanooptomechanics with 2D materials Joseph C Stage, Andrew Lingley, Wataru Nakagawa, Nicholas Borys Suspension of 2D materials over an antenna that is embedded in a dielectric cavity presents new paradigms for nanophotonic engineering and nanooptomechanics in 2D materials with applications that span from ondemand singlephoton emitters to lowtemperature, high Qfactor optomechanical resonators. The hybrid optomechanic and plasmonic architecture can capitalize on the combined effects of strain engineering and nanoplasmonics. Here, the fabrication of metallic antennas embedded in an SiO2 dielectric cavity is described. The method is a modified optical lithography process occurring on the top of a SiO2 film, giving rise to antennas with 13 µm base diameters. The proofofconcept fabrication process demonstrates how the height of the embedded antennae can be tuned with nanometer precision and reveals the next steps for further miniaturization of the antenna and the cavity using electronbeam lithography. Such precise control and miniaturization are crucial for future use of the structures to demonstrate, for example, strongcoupling between plasmons and excitons and nanooptomechanic schemes with 2D materials that aim to use the dipole field between the antennae and a 2D heterostructure to optically control the funneling of excitons and modulate quantum emission phenomena. 

T00.00169: Charge4e superconductivity from nematic superconductors in 2D and 3D Shaokai Jian, Yingyi Huang, Hong Yao Charge4e superconductivity as a novel phase of matter remains elusive so far. Here we show that charge4e phase can arise as a vestigial order above the nematic superconducting transition temperature in timereversalinvariant nematic superconductors. On the one hand, the nontrivial topological defectnematic vortexis energetically favored over the superconducting phase vortex when the nematic stiffness is less than the superfluid stiffness; consequently the charge4e phase emerges by proliferation of nematic vortices upon increasing temperatures. On the other hand, the GinzburgLandau theory of the nematic superconductors has two distinct decoupling channels to either charge4e orders or nematic orders; by analyzing the competition between the effective mass of the charge4e order and the cubic potential of the nematic order, we find a sizable regime where the charge4e order is favored. These two analyses consistently show that nematic superconductors can provide a promising route to realize charge4e phases, which may apply to candidate nematic superconductors such as PbTaSe2 and twisted bilayer graphene. 

T00.00170: Dynamic Response of BioInspired Sutures Richard Nash, Yaning Li Biological suture interfaces are prevalent in various species in nature. Through mechanical modeling and experiments, it was found that the zigzag suture morphology is one key feature to maximize the overall strength and minimize the weight in resisting static mechanical loads. However, in different biological systems, the sutures often carry both static and dynamic loads, such as the cranial suture of mammals and the sutures on the beak of woodpeckers. The goal of this study is to quantify how suture interfaces respond to various dynamic loads. Two dimensional finite element (FE) models of twophase composite sutures with various waviness (i.e. amplitude to wavelength ratio) are developed. Numerical simulations of sutures under both static and dynamic indentation are conducted. One auxetic and one nonauxetic designs are selected, both elastic and elastoplastic material models are used for both phases. The influences of initial velocity, waviness, stiffness ratio between two phases, and auxeticity on the impact resistance of the materials are evaluated. In addition, selected designs are fabricated via a multimaterial 3D printer (Stratasys Connex260). Drop tower mechanical experiments are performed to further quantify the dynamic response of bioinspired composite sutures under various dynamic loads. It is found that shear and auxeticity play a very important role in mitigating impact loads. 

T00.00171: Ultrafast excitedstate dynamics in V_{4}O_{7} Sergiy Lysenko, Alexander Bartenev, Camilo Verbel, Roman Kolodka, Felix Fernandez, Armando Rua We report on the observation of lightinduced excitedstate dynamics in V_{4}O_{7} thin films. This material is correlated oxide with reversible insulatormetal transition (IMT) at temperature T_{c}~237 K. The pumpprobe femtosecond optical spectroscopy within a broad range of the sample temperatures and excitation energies reveals nonthermal lightinduced IMT below the Tc. Nonlinear optical response of V_{4}O_{7 }was found relatively high in both, HighT metallic and LowT insulating phases, showing complex evolution of the photoexcited state. The photoexcitation results in the generation of strong acoustic phonons. The ultrafast formation of a nonequilibrium initial state within ~300 fs in insulating LowT V_{4}O_{7 }results in the subsequent formation of metallic phase within several picoseconds. The mechanism of the IMT is associated with polaronic effects, where the LowT V_{4}O_{7} phase likely originates from strong electronelectron correlations with Wigner crystallization of small polarons. The photoinduced screening of electronic correlations and melting of polaronic order into noncorrelated polaronic states is considered as the most possible pathway for the IMT in V_{4}O_{7}. 

T00.00172: Determining rate dominant steps and synergistic effects in heterogeneous catalytic reactions using nanoporous supports Hongyu Li, Dilip Gersappe Catalysts embedded in porous structures are widely used in materials research and industry. Understanding the dominant step of catalytic chemical reaction rate is crucial for the development of such catalysts. However, the coupling of mass transport and kinetic effects with reactions presents a significant computational challenge. Here, we show that by using a Lattice Boltzmann approach we can develop a model that will allow us to include kinetic effects such as adsorption and desorption of reactants/products, mass transport bottlenecks in the support, and possible pore blocking effects. Further, we show that our model can be used to determine possible synergistic interactions when bimetallic catalysts are used. We use a model system composed of NiPt bimetallic catalysts, that are used to catalyze the reverse water gas shift reaction and methanation through a nanostructured support as an case study for our approach. We compare our results to experimental results and show that our model can be used to explain synergistic effects in this system. 

T00.00173: Midinfrared photodetection using a resonant nanocavity array of coupled surface plasmonphonon polaritons Jacob R Slocum, Chase Ellis, Satya Kachiraju, Ivan Nekrashevich, Long Chang, MyoungHwan Kim Polar dielectric crystals are a promising ingredient in midfar infrared photodetection because strong coupling of infrared light and surface polarized ion vibrations at Reststrahlen band provides a unique channel between photon and phonon via electric charge oscillations. In addition, there are many polar dielectrics in which the Reststrahlen band spreads widely from mid to far infrared spectral range where few photodetection mechanisms are developed. Here, we report midinfrared photodetection from the coupled surface plasmonphonon polariton cavity resonance. The metal (gold) insulator (Si) aperture array on polar dielectric (SiC) crystal forms a FarbryPerot cavity and shows frequencytunable high absorption up to 80% of the optical power at 10 – 12 micron wavelengths. The top metal is connected to an electrode outside the nanocavity array to get a photovoltaic signal. We utilized a tunable quantum cascade laser integrated into an infrared microscope and Fourier transform spectrometer. We ran voltage sensitive needles, in contact with the electrode pads, to a lockin amplifier which could determine the incoming infrared signal when contrasted with the frequency of an optical chopper. We observe microvolt photovoltaic signal with respect to the chopper frequency. 

T00.00174: Discovering new topological materials with heavytransition metals via flux Tiglet Besara, Patrick Lambdin, Matthew Bruenning, Julio Sarmiento Since their first discovery, the amount of topologically protected compounds have expanded and databases have been made of topological insulators and semimetals. Providing highquality materials for their characterization is needed, especially for ARPES. Flux growth is a technique that produces nicely faceted crystals. Here, we report on the exploration of new topological semimetals based on second and third row transition metals. 

T00.00175: Quantifying disorder using a simple model for electrical transport in inhomogeneous 2D superconductors Catherine Phillips, Nicholas Breznay Disorder in 2D materials can dramatically affect the transition into superconducting phases, such as creating a large transverse voltage response near T_{c} even in the absence of a magnetic field. We extend the model of disordered conductors by Parish and Littlewood (Nature 426, 162 (2003)) to granular superconducting materials by adding a sitedependent critical temperature that can be correlated with the local resistivity. Using this model, we are able to visualize the onset of global superconductivity and accompanying changes in material resistivity and patterns of current flow under randomlydistributed degrees of material disorder at different length scales. We also explore the variance in longitudinal and transverse resistance at different disorder scales. Our results provide a framework for quantifying the level of disorder using experimentally reported magnetoresistance and transverse voltage measurements. 

T00.00176: TemperatureResolved Tunneling Spectroscopy Measurements of the Superconducting Energy Gap of Phbased Iron Pnictides Roberto C Ramos, Brett Conti, Dan A Fauni, Keeran O Ramanathan, Ding Hu, Oberon O Wackwitz, Rui Zhang, Luke Conover, Pengcheng Dai Multigap superconductivity has been observed in various ironbased superconductors. The superconducting energy gaps often depend on the particular manner the crystal has been grown as well as how they are contacted with wire leads. We have performed temperatureresolved tunneling spectroscopy down to 2.0 Kelvin on various dopings of BaFe2(As1x Px)2. Many of these measurements were performed using soft point contacts with silver paint and some were made using a wire bonder. Features in the differential conductance that can be identified with superconducting energy gaps were tracked with temperature and compared with those we have previously measured using Kdoped Ba122 iron pnictides. All measurements of this workinprogress were performed fully by undergraduates. 

T00.00177: Temperature dependent optical conductivity of RAlGe (R = La, Ce, Pr) Weyl semimetal Bryan A Valdes, Yejin Kwon, Kim MyoungHwan, Keunki Cho, Beoungki Cho Topological materials are new types of quantum materials on which phases of matter are classified by surface states produced by the topology of the bulk band structure. Among them, topological Weyl semimetals have gained popularity for exhibiting quantum anomalies such as a topological Fermi arc and chiral anomaly from Weyl fermions. Recent material survey extends to magnetic semimetals, especially rareearth based magnetic noncentrosymmetric Weyl semimetals showing a rich topological tunability of Weyl fermions at the lowenergy band structures. Here, we report a strong midfar infrared frequency dependence of the optical conductivity in RAlGe (R = La, Ce, Pr) Weyl semimetal. The optical conductivity is extracted by applying complex KramersKronig analysis on reflection spectrums ranging from a few eV to 1eV. The rareearth compounds RAlGe host either typeI and/or typeII Weyl fermions depending on the rareearth ion. LaAlGe is nonmagnetic while CeAlGe and PrAlGe are ferromagnetic with different easy axes. A comparative study of the optical conductivity on these three compounds reveals distinct infrared spectroscopic features of different types of Weyl semimetals. 

T00.00178: Electronic and Vibronic Properties of Single Molecules in Molecule/Graphene Nanoribbon/Au(111) Heterostructures Saw W Hla, Sineth Premarathna, Kyaw Zin Latt Semiconducting graphene nanoribbon possesses a band gap and thus they have the capability to act as a buffer that effectively decouples molecules of interest electronically from the substrate [1]. Here we investigate the structural, electronic, and vibronic properties of individual parasexiphenyl (6P) molecules separated from a gold surface by graphene nanoribbons in vertically and laterally stacked heterostructures by using a custombuilt low temperature ultrahigh vacuum scanning tunneling microscope. dI/dV tunneling spectroscopy is used to measure the electronic structures of 6P molecules in the molecule/graphene nanoribbon/Au(111) heterostructures. For the vertically stacked heterostructures the energy gap and the molecular orbital locations are found to be much closer to the gas phase values as compared to the molecules directly adsorbed on Au(111) surface and in lateral heterostructures. Moreover, the d2I/dV2 vibrational spectroscopy of 6P reveals a strong vibrational mode associated with the c=c on ring stretching of the molecules. 

T00.00179: Rational Design of BioInspired Nanowire Architectures for Preventing Marine Biofouling Jing Wang Biofouling has a negative impact on human health and economic development. In particular, biofilms in the marine environment grow easily, adhere strongly on most surfaces, and continuously generate adhesive proteins from the living organisms in the film. However, their interactions with nanoscale structures remains unknown. Herein, we present the rational design and fabrication of ZnO/Al_{2}O_{3} coreshell nanowire (NW) architectures to significantly reduce marine biofouling (algae: cyanobacteria and diatoms) and further suppress the biofilm formation by tuning the NW geometry (length, spacing, branching) and surface chemistryTwo mechanisms of the fouling reduction were summarized with geometric and mechanical effect of the NWs: (1) reduced effective settlement area, and (2) mechanical cell penetration. For superhydrophobic NWs, we demonstrated antibiofouling performance for up to 22 days, which is one order of magnitude longer duration than what have been reported in the literature under biofouling environment. A mass diffusion and thermodynamic model was developed to explain and predict the antifouling duration on NWs in the Cassie state. Through the rational control of surface nanoarchitectures, the coupled relationships between wettability, transparency, and antibiofouling performance are identified. We envision that the insights gained from the work can be used to systematically design surfaces that reduce marine biofouling in various industrial settings. 

T00.00180: Universal features of dynamics of localized electronic states Anatoly Obzhirov, Eric J Heller In a number of systems, electronic transport can be viewed as dynamics of localized electronic states. However, there is no universal theory that describes time evolution of localized states. In this work, we present universal features of such motion. They originate from the concept of adiabatic change of character near an avoided crossing. It is shown that localized electronic states move by interchanging positions with adjacent localized states that form an avoided crossing. Avoided crossings formed by two adjacent electronic states would be adiabatic, whereas avoided crossing formed by two distant electronic states would be diabatic. To illustrate this idea, we develop a numerical model based on Anderson localized states. Based on our observations, we discuss universal features of relaxation time. The presented perspective could give new insights on MetalInsulator transitions and electron transport in nanostructures, superlattices, and disordered semiconductors. 

T00.00181: TwoDimensional Charge Density Waves in a SingleLayer Thick Islands of a Molecular Dirac Fermion System Kyaw Zin Latt, Saw Wai, Hla, John A Schlueter, Pierre Darancet Charge density waves have been intensely studied in inorganic materials such as transition metal dichalcogenides however its counterpart in organic materials has yet to be explored in detail. Here we report the finding of a robust two dimensional charge density waves in molecular layers formed by α(BEDTTTF)_{2}I_{3} on a Ag(111) surface. Low temperature scanning tunnelling microscopy images of a multilayer thick α(BEDTTTF)_{2}I_{3} on Ag(111) substrate reveal coexistence of 5a_{0} x 5a_{0} and a_{0} x a_{0} R9° charge density wave patterns commensurate with the underlying molecular lattice at 80 K. Both charge density wave patterns remain in nanosize molecular islands with just a single constituent molecularlayer thickness at 80 K and 5 K. Local tunneling spectroscopy measurements reveal the variation of the gap from 244 meV to 288 meV between the maximum and minimum charge density wave locations. Density functional theory calculations further confirm a vertical positioning of BEDTTTF molecules in the molecular layer. While the observed charge density wave patterns are stable for the defect sites, they can be reversely switched for one molecular lattice site by means of inelastic tunnelling electron energy transfer with the electron energies exceeding 400 meV using a scanning tunneling microscope manipulation scheme. 

T00.00182: PolarizationDriven Asymmetric Electronic Response of Monolayer Graphene to Polymer Zwitterions Probed from Both Sides Nick HightHuf We investigated the nature of graphene surface doping by zwitterionic polymers and the implications of weak inplane and strong throughplane screening using a novel sample geometry that allows direct access to either the graphene or the polymer side of a graphene/polymer interface. Using both Kelvin probe and electrostatic force microscopies, we observed a significant upshift in the Fermi level in graphene of ≈ 260 meV that was dominated by a change in polarizability rather than pure charge transfer with the organic overlayer. This physical picture is supported by density functional theory (DFT) calculations which describe a redistribution of charge in graphene in response to the dipoles of the adsorbed zwitterionic moieties, analogous to a local DC Stark effect. Strong metalliclike screening of the adsorbed dipoles was observed by employing an inverted geometry, an effect identified by DFT to arise from a strongly asymmetric redistribution of charge confined to the side of graphene proximal to the zwitterion dipoles. Transport measurements confirm ntype doping with no significant impact on carrier mobility, thus demonstrating a route to desirable electronic properties in devices that combine graphene with lithographically patterned polymers. 

T00.00183: CONDENSED MATTER PHYSICS


T00.00184: Intrinsic Hard Magnetism and Thermal Stability of ThMn_{12}Structure Permanent Magnet: Density Functional Theory and Monte Carlo Simulation Dorj Odkhuu We propose a possible solution to realize an otherwise unstable ThMn_{12}structure SmFe_{12} permanent magnet through systematic fullpotential density functional theory and Monte Carlo simulations on ternary Sm(Fe,M)_{12} and quaternary Sm(Fe,Co,M)_{12 }compounds (M is a 3d or 3p metal substitute atom). Among the 11 metal substitutable elements (Ti–Ga and Al), only the simple metal Al, rather than the conventional transition metal substitute atoms, is predicted to be optimal. The presence of the Al substitute atoms not only stabilizes the ThMn_{12} structure but also improves further the superior intrinsic magnetic properties to the stateoftheart permanent magnet Nd_{2}Fe_{14}B. A quaternary Sm(Fe,Co,Al)_{12} compound has the uniaxial magnetocrystalline anisotropy (MA) of 9.1 MJ·m^{3}, anisotropy field of 19.2 T, and the magnetic hardness parameter of 2.8 at room temperature, and Curie temperature of 665K. Numerical results of MA and MAdriven hard magnetic properties can be described by the strong spinorbit coupling and orbital angular momentum of the Sm 4felectron orbitals. The other simple metal Ga, which is isoelectronic to Al, makes the present argument rather general, stabilizing the ThMn_{12} structure while still preserving MA uniaxial. 

T00.00185: An observable effect of spin inertia in slow magnetodynamics: Increase of the switching error rates in nanoscale ferromagnets Supriyo Bandyopadhyay, Rahnuma Rahman The celebrated LandauLifshitzGilbert (LLG) equation governing magnetodynamics in ferromagnets tacitly assumes that the angular momentum associated with spin precession relaxes instantaneously when the real or effective magnetic field causing the precession is turned off. This neglect of “spin inertia” is unphysical and would violate energy conservation. Recently, the LLG equation was modified to account for spin inertia and revealed that it gives rise to nutation dynamics lasting for the first few fs to tens of ps at the start of the magnetodynamics in most ferromagnets. Since the nutation is so ephemeral, it was believed that its effect, if any, will be imperceptible in slow magnetodynamics that lasts over ~ns. Here, we show that there is at least one very serious and observable effect of spin inertia even in slow magnetodynamics and it involves the switching error probability associated with flipping the magnetization of a nanoscale ferromagnet with an external agent, such as a magnetic field. The switching may take ~ns to complete when the magnetic field strength is close to the threshold value for switching and yet the effect of spin inertia is felt in the switching error probability. This is because the ultimate fate of a switching trajectory, i.e. whether it results in success or failure, is influenced by what happens in the first few ps of the switching action when nutational dynamics due to spin inertia is dominant. This is reminiscent of chaos theory where final outcomes are very sensitive to initial conditions. Spin inertia increases the switching error probability, which makes the switching more errorprone. This has important technological ramifications for magnetic logic and memory which have little tolerance for switching errors. 

T00.00186: Structural monoclinicity and its coupling to layered magnetism in fewlayer CrI_{3} Gaihua Ye, Zhipeng Ye, Rui He, Wencan Jin, Bowen Yang, Hyun Ho Kim, Adam W Tsen, JiaAn Yan, Xiaoyu Guo, Hongchao Xie, Kai Sun, Liuyan Zhao Stacking symmetry of 2D magnet CrI_{3} plays a key role in defining the magnetic ground states. It has been shown that hydrostatic pressure can switch the layered AFM to FM state via tuning the layer stacking from monoclinic to rhombohedral in bilayer CrI_{3}. A natural question would be: does crystal structure also respond to the magnetic phase transition in Nlayer CrI_{3}? In this work, we investigate layernumber, temperature, and magnetic field dependence of Raman spectra in fewlayer CrI_{3} using polarizationresolved Raman spectroscopy. Instead of focusing on an A_{g} phonon mode at about 129 cm^{1}, we focus on a doublet degenerate E_{g} phonon mode at ~107 cm^{1}. A monoclinic stacking induced degeneracy lift from E_{g} in monolayer to A_{g}+B_{g} in Nlayer (N = 2, 3, 4, …) CrI_{3} is demonstrated in layernumber dependent results. Such a monoclinic structure exhibits a failed attempt to transit into the rhombohedral structure upon cooling. This monoclinic structure undergoes a further monoclinic distortion across the magnetic fieldinduced layered AFMtoFM transition. Our results show that the crystal structure does respond to the magnetic phase transition in Nlayer CrI_{3}. 

T00.00187: Iron/cobalt/goldbased ferrofluids for potential biomedical applications Cody W Miller, William Korzi, Kent Hess, Lynn Krushinski, James Bryant, Maksym Zhukovskyi, Mary S Devadas, Vera N Smolyaninova In ferrofluids, magnetic nanoparticles are suspended in carrier fluid and can orient their magnetic moment in the direction of the applied magnetic field. Iron/cobalt/goldbased ferrofluids were synthesized using two different methods. The size distribution and the composition of the nanoparticles were determined. Magnetization and UVVIS spectra were measured. It was found that FeCoAu nanoparticles have larger magnetic moment then FeCo nanoparticles. Magnetization was used to estimate the thickness of magnetically inactive layer of the nanoparticles. Losses were measured in ac magnetic field at different frequencies and compared with losses in iron oxidebased ferrofluids. Higher magnetic moment and losses of FeCoAubased ferrofluids at higher frequencies can lead to the potential biomedical applications of these ferrofluids such as magnetic drug delivery and hyperthermia treatment. 

T00.00188: Reduced effective magnetization and slowrelaxing impurity damping in strained γFe_{2}O_{3} Manuel Müller, Monika Scheufele, Janine Gückelhorn, Luis Flacke, Andreas Haslberger, Mathias Weiler, Hans Huebl, Stephan Gepraegs, Rudolf Gross, Matthias K Althammer The ferrimagnetic insulating iron oxide phase γFe_{2}O_{3} (maghemite) finds application as a magnetic nanoparticle in recording media. We report the successful pulsed laser deposition (PLD) of strained tetragonal maghemite thin films on cubic MgO (001) substrates. To investigate its magnetization dynamic, we perform vector network analyzer (VNA) based broadband ferromagnetic resonance experiments and study the magnetization dynamics parameters as function of layer thickness and temperature in a cryogenic setup. We verify the expected temperaturedependence of the slowrelaxing impurity contribution and observe a complete freezeout of slow relaxing impurity damping at T=2.5 K. Furthermore, we observe a straininduced reduction and signreversal of the effective magnetization for cryogenic temperatures. The reduced effective magnetization of maghemite makes it an interesting material platform as the associated nearly circular magnetization precession reduces nonlinear magnon damping effects as for example recently demonstrated by us in allelectrical magnon transport experiments [1]. 

T00.00189: DzyaloshinskiiMoriya interaction in Pt/Co/Re films Akiyo Nomura, Tenghua Gao, Satoshi Haku, Kazuya Ando We report the DzyaloshinskiiMoriya interaction (DMI) in Pt/Co/Re films. The DMI has attracted great interest in recent years due to its fundamental role in the stabilization of magnetic skyrmions, which are promising building blocks for nextgeneration data storage and information processing devices. The DMI at ferromagneticmetal/heavymetal (FM/HM) interfaces is of particular practical importance since the DMI can be designed by selecting the materials for the HM and FM layers. In particular, an additive large DMI can be achieved in HM/FM/HM systems when the top and bottom interfaces show the same sign of the interfacial DMI. Here, we investigate the DMI in Pt/Co/Re films to explore the possibility of achieving a large DMI. By measuring the currentinduced hysteresis loop shift, we find that the interfacial DMI in the Pt/Co/Re structure is as large as that of Ir/Co/Pt asymmetric multilayers, which is widely known for its large DMI. The large DMI in this system is due to the additional DMI at the Pt/Co and Co/Re interfaces, which is consistent with theoretical predictions. This result provides useful information for designing the size and stabilizing magnetic skyrmions, as well as for understanding the DMI at interfaces. 

T00.00190: Crystal and magnetic structure of possible Weyl semimetal NdAlGe Chetan Dhital, John F DiTusa, Rebecca L Dally, Huibo Cao, Yan Wu, Qiang Zhang, Ramakanta Chapai, Sunil K Karna Rare earth compounds are known to exhibit varieties of exciting electronic and magnetic properties arising from complex interplay of conducting charges, usually derived from d or plike bands and more localized felectrons. Added variety of interesting states comes from differences in lattice symmetry, spinorbit interactions, crystalline electric fields, and the related magnetocrystalline anisotropy. A recent addition to such exciting properties is the theoretical prediction and experimental verification magnetic Weyl fermion state in RAlGe (R=Rare earth) family of compounds. Previous investigations of this class of compounds were limited to R=La, Ce and Pr. In this work, we extend this line of inquiry to isostructural NdAlGe to explore how these electronic and magnetic properties vary as the size of the rare earth element and consequently the position of the felectron states with respect to the Fermi level is varied. I will present the crystal structure and magnetic behavior of NdAlGe. Our work will be crucial to understand the interplay between electronic topology and magnetism in noncentrosymmetric rare earth magnets. 

T00.00191: Probing Collinear and NonCollinear Magnetic Configurations of 3d Transition Metal Adlayers Supported on MnGa Terminated Ni_{2}MnGa (001) Surface JOYDIPTO BHATTACHARYA The study of magnetic adlayers supported on magnetic and nonmagnetic elemental surfaces has attracted lot of attention for their interesting and sometimes complex magnetic properties. Here, we have carried out electronic structure calculations to study and analyze the collinear and noncollinear magnetic ordering of a monolayer of transition metal (TM) atoms (Cr, Mn,Fe, Co,Ni), on the MnGa terminated surface of ferromagnetic Heusler alloy Ni_{2}MnGa. We find that all of these adatoms on the surface tend to have collinear configurations . However, only for the Cr adatoms we find a local minimum of energy for the noncollinear magnetic ordering, where the two Cr adatoms are AFM coupled to each other and their magnetization axes are rotated with a rotation angle 72^{°} and 79^{°} with respect to the Z axis. Further, we observe that there are two sets of collinear configurations (1) the Cr and Mn atoms which are antiferromagnetically (AFM) coupled, whereas (2) the Fe , Co and Ni adatoms which are ferromagetically (FM) coupled to the substrate. This behavior can be understood, from the AlexanderAnderson model. We further probe the dependence of two parameters, namely, surface termination and thickness of the adlayers, on the collinear magnetic properties for two adatoms, Cr and Fe. 

T00.00192: The Triskyrmion Pierce E Wickenden Skyrmions are topologically nontrivial solutions that emerge in magnetic solids, characterized by an integer called the topological charge, Q. Motivated by the discoveries in [1], we wish to study the Q=3 solution, i.e the “triskyrmion”, a bound state of three Q=1 skyrmions. We explore the properties of the triskyrmion using the explicit spin components, following the model of Belavin and Polyakov (BP model) [2]. We investigate the triskyrmion stability via the minimization of the energy using the routine from [3]. We also explore the properties of other Q=3 structures, which are distinct from the triskyrmion. In addition to studying the triskyrmion, which can potentially be used for the same computing applications as the skyrmion, this work outlines the analytical framework that serves as a starting point for the study of other exotic classes of solutions within the BP model. 

T00.00193: Angle Dependent Switching of Low Energy Barrier Magnetic Tunnel Junctions Hao Chen, Sara Majetich, Bradley Parks Low energy barrier magnetic tunnel junctions (MTJs) have a stochastically fluctuating magnetoresistance (MR) due to thermally activated reversal of the free layer. Here we describe the angular dependence of switching for MTJs with inplane magnetization, where the fixed layer consisted of a synthetic antiferromagnet pinned by antiferromagnetic IrMn. 60 x 90 nm devices were patterned by electron beam lithography and ion milling. MR loops were recorded at different field angles to calculate the angle between the free layer magnetization direction and the easy axis (major axis of the ellipse). While easy axis loops showed single sharp switching fields, hard axis loops had gradual changes in resistance due to slowly rotated free layer magnetization. The switching field as a function of the x (easy axis) and y (hard axis) components of the applied field is analyzed where the IrMn layer contributes a cubiclike 4fold anisotropy field energy term. There is also an asymmetry in the switching field in the ± H_{y} directions associated with exchange bias. Telegraphing was only observed for a small angular region near the +H_{y} (hard) axis, where we combined all the mentioned energy terms to determine the two telegraphing positions. 

T00.00194: Disorderinduced phases in nonKramers rareearth pyrochlores. Victor Porée, Edward Riordan, Elsa Lhotel, Sylvain Petit, Michel Kenzelmann, Romain Sibille The 2in2out local constrain in spin ices brings about a manifold of degenerate ground states, with spin correlations giving rise to emergent magnetostatics. In rare earth pyrochlores, the introduction of transverse fields in the Hamiltonian offers a possible route to promote quantum fluctuations leading toward the quantum spin ice (QSI) state, a lattice analogue of quantum electrodynamics. It has been proposed theoretically, and argued experimentally, that in the case of nonKramers magnetic ions, nonmagnetic disorder can generate such transverse fields, allowing the exploration of socalled disorderedinduced quantum spin liquids (QSLs). 

T00.00195: Electronic, magnetic, and structural properties of CrMnSb_{0.5}Si_{0.5} Pavel Lukashev, Lukas Stuelke, Lilit Margaryan, Parashu R Kharel, Paul Shand Halfmetallic Heusler compounds are among the most actively studied materials for applications in spinbased electronics. Largely, this is due to their high Curie temperature, and relative ease of fabrication. Here we theoretically study one such alloy CrMnSb_{0.5}Si_{0.5}. It is shown that the parent compound CrMnSb is not halfmetallic in its ground state, however it undergoes a halfmetallic transition under a uniform compression of ~1.5%. On practice, such compression could be induced by substituting the nonmagnetic element (Sb) with another nonmagnetic element of smaller radius (Si), e.g. in CrMnSb_{0.5}Si_{0.5}. Here, we demonstrate a thermodynamic stability of this compound, its halfmetallic electronic structure, and ferrimagnetic alignment. At the same time, it is shown that in thinfilm geometry the spinpolarization of this material is reduced due to the emergence of surface states in the minorityspin energy gap. These results may be useful for researchers working on practical applications in the field of spintronics. 

T00.00196: Preparation of Atomically Clean van der Waals Based WTe_{2}/FGT Heterostructures for SpinOrbit Torque Switching Studies Sean Yuan, IHsuan h Kao, Ryan Muzzio, James H Edgar, Joshua E Goldberger, Jiaqiang Yan, Jinwoo Hwang, Jyoti Katoch, Simranjeet Singh Layered materials with lowsymmetry crystal structure, such as WTe_{2} and MoTe_{2}, are energy efficient spin source materials for spintronicsbased memory and logic devices. An atomically sharp interface in nonmagnetic/magnetic bilayer structures, routinely used in spinorbit torque (SOT) switching devices, is essential to suppress the spin dephasing at the interfaces and subsequently enhance the SOT efficiency for spintronics applications. We will present experimental results showing the fabrication of SOT switching devices constructed out of vdW based heterostructures of WTe_{2 }and Fe_{3}GeTe_{2 }(FGT) with atomically clean interfaces. Furthermore, we will present our SOT switching experiments that are aimed at demonstrating an efficient and fieldfree magnetization switching of FGT, which is a layered 2D magnet with strong perpendicular magnetic anisotropy. Our work is the first step towards realizing allvdW based spintronic devices that are ultrathin and need ultralow power consumption for its operation. 

T00.00197: Magnetic anisotropy in permalloy antidot square array investigated by ROTMOKE and MTXM Tianye Wang, HeeSung Han, Cong Su, Qian Li, Mengmeng Yang, Weilun Chao, Xixiang Zhang, Chanyong Hwang, Alex K Zettl, MiYoung Im, Zi Q. Qiu Magnetic anisotropy of Permalloy (Py) antidot square array was investigated systematically by a torquemetry method using Rotation MagnetoOptic Kerr Effect (ROTMOKE). In addition to the expected 4fold magnetic anisotropy, we find that there also exists an unexpected uniaxial magnetic anisotropy in ROTMOKE result. By a careful analysis, we show that this uniaxial anisotropy is a general artifact of torquemetry methods due to nonuniform magnetizations which usually exist in patterned artificial magnetic structures. We show that both the 4fold anisotropy and the artifact of the uniaxial anisotropy are due to the periodic wiggling of the magnetization in space which is confirmed by Magnetic Transmission Soft Xray Microscopy (MTXM) and supported by micromagnetic simulations via MuMax3. Simulations also reproduce the artifact of the uniaxial anisotropy in ROTMOKE result. A simplified model is then developed based on the periodic wiggling of the magnetizations and successfully explores the physical origin of the fielddependent 4fold anisotropy and the artifact of the uniaxial anisotropy. 

T00.00198: FirstPrinciples Study of Single Molecule Magnet Mn_{12} on Graphene with Defects Morgan Hale, DaVonne Henry, Paola Barbara, Amy Y Liu Transport through graphene devices can be used to probe the electronic and magnetic properties of molecules deposited on the graphene surface. Previous experimental work on the single molecule magnet (SMM) Mn_{12} deposited on graphene showed that the substrateSMM charge transfer and the carrier mobility of the graphene are sensitive to the choice of ligand [1], consistent with trends found in density functional theory (DFT) studies [2, 3]. Motivated by recent experiments [4] that showed charge transfer inconsistent with prior reports, we consider whether defects in graphene could account for the discrepancy. In this work, DFT calculations were carried out to characterize [Mn_{12}O_{12}(COOR)_{16}](H_{2}O)_{4} deposited on graphene with a vacancy defect. Results of optimized structures, energetics, magnet properties, and charge transfer will be presented for ligands R = H, CH_{3}, CHCl_{2}. 

T00.00199: Syntheses and Characterization of CoreShell IronBased Magnetic Nanoparticles Coated by Carbon Harutyun Gyulasanyan, Gayane Chilingaryan, Aram Manukyan, Franco Iglesias, Calixto Alvarado, Oscar O Bernal, Armen Kocharian In recent years, there has been a growing interest in synthesizing of novel ironbased nanoparticles and nanocomposites with high efficiency of thermal energy transfer suitable for use in magnetic fluid hyperthermia. Here we investigate structural and magnetic properties of Carboncoated ferromagnetic (FeFe3O4)@C “coreshell” nanocomposites synthesized by a solidphase pyrolysis (SPP) of Iron phthalocyanine (FeC32H16N8) molecules. This product of pyrolysis additionally annealed at 250°C under oxygen media produces (Fe3O4) shell on Fe nanoparticles. We conducted a thorough investigation of structural and magnetic properties of these materials using Xray diffraction (XRD), Raman spectroscopy, magnetometry, electron paramagnetic and ferromagnetic resonances (EPR, FMR). The characteristics of magnetic heating of waterbased solutions with different concentrations of synthesized nanocomposites under the influence of an external magnetic field have been studied. The magnetic characteristics such as saturation magnetization and coercivity as well as the specific absorption rate (SAR) make these materials attractive for magnetic hyperthermia applications. 

T00.00200: Spin cat states in ferromagnetic insulator Sanchar Sharma, Victor Bittencourt, Alexy D Karenowska, Silvia G Viola Kusminskiy Generating nonclassical states in macroscopic systems is a longstanding challenge. A promising platform in the context of this quest are novel hybrid systems based on magnetic dielectrics, where photons can couple strongly and coherently to magnetic excitations, although a nonclassical state therein is yet to be observed. We propose a scheme to generate a magnetization cat state, i.e., a quantum superposition of two distinct magnetization directions, using a conventional setup of a macroscopic ferromagnet in a microwave cavity. Our scheme uses the ground state of an ellipsoid shaped magnet, which displays anisotropic quantum fluctuations akin to a squeezed vacuum. The magnetization collapses to a cat state by either a single photon or a parity measurement of the microwave cavity state. We find that a cat state with two components separated by 5 hbars is feasible and briefly discuss potential experimental setups that can achieve it. 

T00.00201: Magnetic, Structural, and Magnetoelectric Coupling Properties of Aliovalent Substituted Multiferroic BiFeO_{3 }nanoparticles Imaddin A AlOmari, Manoj Mohan, Salim H AlHarthi, Myo T.Z. Myint, Bibin Jacob, Dhanyaprabha K C, Hysen Thomas Multiferroics (MF) are materials that show spontaneous magnetic and electric ordering in the same phase. The coexistence of different functionalities (ferroelectricity, ferroelasticity and ferromagnetism) in a single phase makes MF a remarkable candidate for the next generation electronic applications. Nanoparticles of multiferroic Bi_{1x}CaxFeO_{3} (x between 0.0 and 0.4) have been synthesized and the kinetics of magnetoelectric (ME) coupling in Bismuth Ferrite (BiFeO_{3}) with the substitution of aliovalent calcium ion has been investigated. Substitution induced structural transition from rhombohedral to the orthorhombic system is observed. The crystallite size obtained for the samples is well below the spiral spin wave length (62 nm) of Bi_{1x}Ca_{x}FeO_{3} system. Comparison of dielectric and XPS studies reveals oxygen vacancies can be reduced upon calcium substitution upto 20at%. The ME coupling studies reveals a systematic increase in ME coefficient can be achieved up to 20 at% of calcium substitution, which is close to the theoretical predictions reported in the literature. We found that calcium ion is a suitable substituent to improve the properties by structural modification and control of parasitic phases as well as interstitial defects formation. The resulting structural, dielectric, magnetic and magnetoelectric coupling properties have been explained in terms of chemical pressure originating from the substituent ion. 

T00.00202: Thermal transport of the frustrated spinchain mineral linarite: Magnetic heat transport and strong spinphonon scattering Christian Hess, Matthias Gillig, XiaoChen Hong, Piyush Sakrikar, Gael Bastien, Anja U Wolter, Leonie Heinze, Satoshi Nishimoto, Bernd Büchner The mineral linarite is a prototype frustrated spin1/2 chain compound with competing ferromagnetic nearestneighbor and antiferromagnetic nextnearestneighbor interactions with magnetic ordering below T_{N}=2.8 K in a mutliferroic elliptical spinspiral ground state. Upon the application of a magnetic field along the spinchain direction, distinct magnetically ordered phases can be induced. We report the thermal conductivity κ of this material across the magnetic phase diagram as well as in the paramagnetic regime. We found that in linarite the heat is carried mainly by phonons but shows a peculiar nonmonotonic behavior in field. In particular, κ is highly suppressed at the magnetic phase boundaries, indicative of strong scattering of the phonons off critical magnetic fluctuations. Even at temperatures far above the magnetically ordered phases, this leads to a reduction of the phononic thermal conductivity. The mean free path due to spinphonon scattering (l_{spinphonon}) was determined as function of temperature. A power law behavior was observed mainly above 0.5 K indicating the thermal activation of spin fluctuations. In the critical regime close to the saturation field, l_{spinphonon} shows a 1/T dependence. Furthermore, a magnon thermal transport channel was verified in the helical magnetic phase. We estimate a magnon mean free path which corresponds to about 1000 lattice spacings. 

T00.00203: Firstprinciples study of electronic structure and magnetic properties of L10ordered FeNi, FePd, and FePt alloys Abdalla A Obeidat Using the firstprinciples method, we study the structural, electronic, and magnetic properties of three different spin configurations of the L1_{0} phase of FeM alloys (M=Ni, Pd, or Pt). The calculations have been investigated using Density Functional Theory (DFT) and using several exchangecorrelation functional. It is found that the PBE has the most accurate results for lattice parameters comparing with experimental values. Also, in FeM (M=Ni, Pd, or Pt) alloys, the most stable is the Ferromagnetic (FM) configuration with all spin directions aligned perpendicular to the (001) plane. Our calculations indicate that an antiferromagnetic (AFM) state can be achieved in FeM (M=Ni, Pd, or Pt) by a small variation in tetragonality ratio c/a (from 0.98 to 0.92). In AFM model, a pseudogap is observed just below fermi energy for each alloy. Our calculations show large magnetocrystalline anisotropies for FePt in the order of 3 meV/f.u. FePd and FeNi show a somewhat lower value in the range of 0.1 to 0.4 meV/f.u. Furthermore, Heisenberg exchanges interactions are calculated from first principles and Green's functions formalism. 

T00.00204: Phonon manipulating magnon transports in magnetic multilayers through coupled Boltzmann approach Tian Tian, Chao Chen, Yuheng Li, Jianwei Zhang The collective elementary excitations of magnetic order, magnons, the quanta of spinwave, are bosonic and carry spin angular momentum. Becoming an ideal spintronic device information carrier with low energy dissipations in ferromagnetic materials(like YIG). The scattering of phonons, in particular, the surface acoustic wave SAW, excites and regulates magnon and couples the transport channels of phonons and magnetrons through the magnetoelastic action. Which emerges a new method of magnons controlling. In this paper, within the framework of nonequilibrium Boltzmann transport, we address on the physical mechanism of how coupled phonons regulate and enhance the effects of magnon flow and propagation distance; as well as, the conversion mechanism of spin/magnon/phonon in magnetic multilayer film materials. We also study frequencies of coupled phonons that affect magnon's relaxation in kspace and by using external gradient field methods to control magnon transport. Based on quantum exchange interaction, we established a nonequilibrium magnon/spin/phonon threephase coupled Boltzmann equations to calculate the transport behavior in the multilayer film system. The physical core content of this paper focuses on nonequilibrium magnon propagation, coupled phonon excitation magnon, and material parameter controlling. 

T00.00205: When can localized spins interacting with conduction electrons in ferro or antiferromagnets be described classically via the LandauLifshitz equation: Transition from quantum manybody entangled to quantumclassical nonequilibrium states Abhin Suresh, Priyanka Mondal, Branislav K Nikolic The nonequilibrium dynamics of localized spins within magnetic materials are standardly described by the LandauLifshitz (LL) equation. However, spin is a quantum degree of freedom, and its effects exist for all spin S less than infinity. To understand the limits of LL equation, we compare LL trajectories to quantum expectation values of localized spin operators in the presence of electrons. We start from the unentangled ground state of localized spins as the initial condition and apply a magnetic field to initiate dynamics. This reveals that quantumclassical dynamics can faithfully reproduce fully quantum dynamics in the FM case, but only when spin S, Heisenberg exchange between localized spins and sd exchange are sufficiently small. Increasing any of these parameters can lead to deviations, which are explained by the growth of entanglement between localized spins and between them and electrons. Including thermal fluctuations only delays the time at which entanglement grows. In the AFM case, substantial deviations appear even at early times, despite starting from unentangled Neel state. 

T00.00206: Interaction of gapless spin waves and a domain wall in an easycone ferromagnet Wooyon Kim, Gyungchoon Go, Se Kwon Kim We theoretically study the interaction of spin waves and a domain wall in a onedimensional easycone ferromagnet. Specifically, we obtain the scattering matrix of gapless spin waves on top of a domain wall within the nonequilibrium Green function formalism, which is found to exhibit finite reflection in contrast to the wellknown perfect transmission of gapful spin waves through a domain wall in easyaxis magnets. Based on the obtained scattering properties, we study the thermalmagnondriven dynamics of a domain wall subjected to a thermal bias within the LandauBüttiker formalism, where transmitted magnons are shown to exert the magnonic torque on the domain wall and thereby drive it with the velocity linear to the applied thermal bias. The peculiar gapless nature of spin waves in easycone magnets enables the thermallydriven domainwall motion even at low temperatures, differing from the easyaxis case where the domainwall velocity is exponentially suppressed at low temperatures. Our work suggests that easycone magnets can serve as a versatile platform to study the interaction of gapless spin waves and nonlinear excitations such as vortices and skyrmions and thereby realize lowtemperature magnonrelated phenomena. 

T00.00207: Electronic and magnetic properties of CoFeV_{0.5}Mn_{0.5}Si: experiment and theory Parashu R Kharel, Gavin Baker, Matthew Flesche, Adam Ramker, Young Moua, Shah Valloppilly, Paul Shand, Pavel Lukashev Halfmetallic Heusler alloys have been investigated as potential materials for spintransportbased devices. We have synthesized one such material, CoFeV_{0.5}Mn_{0.5}Si, using arc melting and highvacuum annealing at 600^{o}C for 24 hours. First principles calculation indicates that CoFeV_{0.5}Mn_{0.5}Si is nearly halfmetallic with the degree of spin polarization of about 93%. The annealed sample exhibits cubic crystal structure without disorder and secondary phases. It shows ferromagnetic order at room temperature with the Curie temperature of 657 K and saturation magnetization of 92 emu/g (3.06 μ_{B}/f.u). The observed structural and magnetic properties are consistent with the theoretical results. Our results indicate that CoFeV_{0.5}Mn_{0.5}Si has a potential for room temperature spintransportbased devices. 

T00.00208: Light and microwave driven spin current detection in FeGaB thin films Prabesh Bajracharya, vinay Sharma, Weipeng Wu, Anthony Johnson, Matthias Benjamin Jungfleisch, Ramesh C Budhani Measurements of frequency dependent ferromagnetic resonance (FMR), spin pumping driven dc voltage (V_{dc}) and femtosecond lightpulseinduced terahertz (THz) emission are reported for amorphous films of Fe_{78}Ga_{13}B_{9 }(FeGaB) alloy to address the phenomenon of selfinduced inverse spin Hall effect (ISHE) in plain films of metallic ferromagnets. The asymmetric V_{dc} signal draws contributions from rectification effects of a ≈ 0.4 % anisotropic magnetoresistance and a large (≈ 54 nΩ.m) anomalous Hall resistivity (AHR) [1] of these films which ride over the effect of spin – orbit coupling driven spintocharge conversion near the film – substrate interface. The femtosecond lightpulseinduced THz emission experiments reveal a decreasing THz signal with increasing FeGaB thickness. This study will be very useful for fully understanding the spin pumping induced dc voltages in metallic ferromagnets with disordered interfaces and large anomalous Hall effect. 

T00.00209: Effects of nonuniform vacancy distribution on diluted hexaferrites. Sean T Anderson Recent experiments [1] on the diluted hexaferrite PbFe_{12x}Ga_{x}O_{19} have demonstrated that the magnetic ordering temperature T_{c} vanishes as T_{c}~(x_{c}x)^{2/3} with increasing Ga concentration x. The critical concentration x_{c} agrees well with the percolation threshold of the underlying lattice. However, Monte Carlo simulations of a randomly diluted Heisenberg model [2] were unable to reproduce the experimentally observed 2/3power law. Here, we explore whether unequal occupations by Ga atoms of the five distinct Fe sublattices in the hexaferrite crystal structure can explain the experiments. To this end, we perform extensive Monte Carlo simulations of Heisenberg models on hexaferrite lattices with nonuniform dilution. 

T00.00210: Skyrmionbased stochastic neurons and their mutual interactions Kang Wang, Yiou Zhang, Vineetha S Bheemarasetty, Shiyu Zhou, SeeChen Ying, Gang Xiao Magnetic skyrmions are of great interest due to their desirable features for use in postvonNeumann computing devices. Implementing skyrmionic devices experimentally requires functionalities of skyrmions with effective controls. Although various skyrmionic devices have been proposed based on the dynamic motion of skyrmions, little progress has been reported in the implementation of such devices owing to challenges in the precise control over skyrmion motion. In this talk, we will examine the local dynamics of a single skyrmion interacting with local pinning centers confining a skyrmion in a magnetic thin film. We will show that a single skyrmion behaves like a stochastic neuron and there exists a mutual coupling between multiple stochastic neurons. The local dynamics of single skyrmions and their coupling strength can be controlled by using an applied magnetic field and a spin current. These properties of skyrmions can be taken advantage of in computing applications. 

T00.00211: An electronic noise study of single magnetic skyrmions Kang Wang, Yiou Zhang, Vineetha S Bheemarasetty, SeeChen Ying, Gang Xiao While pinning centers tend to impede skyrmion motion, they are essential to reliably positioning and guiding skyrmions as well as to avoiding skyrmion annihilation. A detailed understanding of interactions between skyrmions and pinning centers is hence crucial. In this talk, we will report an electronic noise study of single magnetic skyrmions interacting with local pinning centers in magnetic thin films with different pinning strengths. While telegraph noises are observed in the weak and intermediatepinning regimes, the 1/f noise of a single skyrmion is noticed in the strongpinning regime. We examine their microscopic origins through the complementary magnetic imaging as well as micromagnetic simulation studies. 

T00.00212: Voltagecontrolled Néel vector rotation in zero magnetic field in highT_{N} magnetoelectric thin films Syed Qamar Abbas Shah, Ather Mahmood, Will Echtenkamp, Junlei Wang, Mike Street, Takashi Komesu, Peter A Dowben, Pratyush P Buragohain, Haidong Lu, Alexei Gruverman, Arun Parthasarathy, Shaloo Rakheja, Christian Binek Multifunctional thin films of boron (B) doped Cr_{2}O_{3} exhibit voltagecontrolled and nonvolatile Néel vector reorientation in the absence of a magnetic field, H. Toggling of antiferromagnetic states is demonstrated in prototype spin Hall magnetoresistance device structures at CMOS compatible temperatures between 300 and 400 K. The boundary magnetization associated with the Néel vector orientation serves as state variable which is read via magnetoresistive detection in a Pt Hall bar adjacent to the B:Cr_{2}O_{3} film. Various characterization techniques support that voltage controlled, nonvolatile Néel vector rotation takes place at hightemperature in H = 0. Theoretical modeling estimates switching speeds of about 100 ps making B:Cr_{2}O_{3} a promising multifunctional singlephase material for energy efficient nonvolatile CMOS compatible memory applications. 

T00.00213: NonLocal Spin Transport Driven by Spin Seebeck Effect in a Heisenberg Antiferromagnet Hossein Taghinejad, Vikram Nagarajan, Ella O Lachman, Eran Maniv, Luke Pritchard Cairns, Yoshiharu Krockenberger, James G Analytis In contrast to the tremendous success of spintronics in the nonvolatile data storage, transport and processing of data via the spin degree of freedom have not excelled proportionally. Such an imbalance stems primarily from the short (< 1µm) diffusion length of spin carried by conduction electrons in (magnetic) metals, which are integral building blocks of contemporary spintronic devices such as spin valves. This shortcoming has turned attentions towards the use of magnetic insulators in which, instead of conduction electrons, information can be carried over a longer distance by the collective excitations of atomic spins, that is the spin wave. 

T00.00214: Firstprinciples calculation and theoretical study of van der Waals magnets and their heterostructures Jimin Qian, Ting Cao, Yusen Ye Van der Waals magnets hold unusual electronic properties promising for spintronic applications. In this work, we use firstprinciples density functional theory (DFT) calculations to study van der Waals magnets and their heterostructure. The interplay between magnetism and interlayer stacking configurations has been analyzed in a theoretical framework. Structural relaxation effects have been investigated in the heterostructure and further simulated through a continuum model. We discuss how our theoretical work can be observed in experiments. 

T00.00215: Emergent spin phenomena in nonhermitian RashbaHubbard model Saikat Banerjee, Avadh B Saxena Nonhermitian Hamiltonians have recently become important not just in photonics but also in condensed matter systems. In this context, we introduce a general model for a nonhermitian tightbinding Hamiltonian with Rashba spinorbit coupling. In the presence of a Hubbard repulsion term, we explore the lowenergy effective spin exchange and DzyloshinskiiMoriya interaction in this model. Depending on the choice of the lattice, we find that spin noncollinearity and frustration are modified. Finally, we discuss the possible material realization of the model. 

T00.00216: Magneticfieldinduced ferroelectric states in centrosymmetric R_{2}BaCuO_{5} (R = Dy and Ho) Premakumar Yanda The linear magnetoelectric effect and multiferroicity phenomena occur independently due to breaking inversion symmetry below the magnetically ordered state of either transition metal or rareearth ions. Here, I present the occurrence of a linear magnetoelectric effect and magnetic fieldinduced ferromagnetism and ferroelectricity below the 4f3d coupled magnetic state in the orthorhombic green phases R_{2}BaCuO_{5} (R = Dy and Ho). They undergo a longrange antiferromagnetic ordering of Cu^{2+} ( = 18.5 K and = 17.5 K) and R^{3+} ions ( = 10.7 K and = 8 K) for Dy and Ho compounds, respectively. Neutron diffraction study reveals that these compounds undergo a firstorder magnetic transition from the hightemperature centrosymmetric antiferromagnetic phase ( ) to the lowtemperature noncentrosymmetric phases, (Dy) and (Ho), which allow linear magnetoelectric coupling. This is consistent with fieldinduced electric polarization, below, which varies linearly up to ~1.2 T. Above a critical field (H_{c} > 1.2 T), both compounds exhibit metamagnetic transitions with magnetization close to the saturation value, M_{s} ~ 10.1 µ_{B}/f.u. (Dy) and ~ 11.8 µ_{B}/f.u. (Ho) at 7 T. Above the metamagnetic transition, a new polar state appears with large electric polarization indicating fieldinduced ferroelectricity. I discuss the important role of 4f3d coupling in determining the ground state magnetic structure responsible for the magnetoelectric coupling in both compounds. 

T00.00217: Chiral Helimagnetism and the Hall effect in Cr_{1/3}NbS_{2}. Daniel A Mayoh, Juba Bouaziz, Amelia E Hall, Julie Staunton, Martin R Lees, Geetha Balakrishnan Noncentrosymmetric magnetic systems have been found to host a variety of exotic, and in some cases topologically protected, magnetic states such as skyrmion lattices, bimerons, chiral solitons and helimagnetism to list a few. Materials that have faced increased scrutiny in recent years for their magnetism are twodimensional (2D) materials. Of these, the intercalated transition metal dichalcogenides (TMDCs) are an interesting class exhibiting ferromagnetic or antiferromagnetic ordering and some of them are also known to host chiral soliton lattices. Cr_{1/3}NbS_{2} is an example of a 2D TMDC where the structure consists predominately of layers of Nb and S where the Cr atoms have been intercalated between the layers. Cr_{1/3}NbS_{2} is known to exhibit chiral helimagnetic ordering as well as a chiral soliton lattice [1]. Conventional and planar Hall measurements can provide valuable insight into the presence of exotic spin structures in chiral magnets. We present our recent results of an extensive study of the Hall effect in single crystal Cr_{1/3}NbS_{2} [2]. 

T00.00218: Twistassisted tunability and enhanced ferromagnetism in a 2D Van Der Waal's Heterostructure Subhasmita Kar, Soumya Jyoti Ray The twodimensional (2D) Van Der Waal’s heterostructures have recently attracted considerable attention due to its novel and extraordinary properties. In this work, the density functional theory (DFT) calculations have been used to explore the electronic and magnetic properties of Cr_{2}Ge_{2}Te_{6 }(CGT)/Graphene vertical heterostructure under different twist angles. We studied CGT/Graphene heterostructures, where each layer has been realized in experiments. The CGT monolayer has recently drawn much attention due to its 2D longrange ferromagnetic (FM) order. However, its Curie temperature (T_{c}) is too low (∼61 K) for practical spintronic applications. The study of this vertical junctions demonstrated that interlayer interactions led to the formation of strong spin polarization, electronic phase transition and a T_{c }value of ∼133 K at a twist angle of 8.95^{0}. Furthermore, we proposed that the ferromagnetic property of this 2D magnetic semiconductor can be strongly enhanced in van der Waals heterostructures by attaching a nonmagnetic monolayer. Therefore, the integration of ferromagnetic and nonmagnetic properties in a single 2D material will be beneficial for practical applications in spintronics as well as storage devices. 

T00.00219: NonHermitian band topology from momentumdependent relaxation in two dimensional metals with spiral magnetism Johannes Mitscherling, Walter Metzner We present the emergence of nonHermitian band topology in a twodimensional metal with planar spiral magnetism due to a momentumdependent relaxation rate. A sufficiently strong momentum dependence of the relaxation rate leads to exceptional points in the Brillouin zone, where the Hamiltonian is nondiagonalizable. The exceptional points appear in pairs with opposite topological charges and are connected by arcshaped branch cuts. We show that exceptional points inside hole and electron pockets, which are generally present in a spiral magnetic state with a small magnetic gap, can cause a drastic change of the Fermi surface topology by merging those pockets at isolated points in the Brillouin zone. The spectral function observed in photoemission exhibits Fermi arcs. Its momentum dependence is smooth  despite of the nonanalyticities in the complex quasiparticle band structure. 

T00.00220: Tunable Optical Properties in Magnetic Phosphorene Puja Kumari, Soumya Jyoti Ray Over the past few years have been seen the discovery, investigation, and utilization of a greater variety of twodimensional (2D) materials. These materials are atomicscale thickness layered crystalline structures with inplane atoms covalently bonded to one another and adjacent layers to combine with weak Van der Waals interactions. These materials are unique properties and the discovery of graphene built a platform to investigate 2D materials experimentally in synthesizing, transferring, and characterizing, as well as theoretically in electronic structure, magnetism, optoelectronics, and many more. Among the newest members of the 2D materials family, phosphorene has shown highly anisotropic properties and unique optical and optoelectronic properties through its puckered structure. In this work, we have systematically studied the electronic, magnetic, and optical properties of phosphorene substituted with transition metal atoms through firstprinciple based density functional theory. We have designed our system by replacing the phosphorus atoms with transition metal atoms in 2.7% and 11.1% substitution concentrations. As a transition metal atom is substituted, the semiconductor nature of phosphorene becomes bipolar magnetic (2.7% Cr substitution), halfmetallic (2.7%, 11.1% V substitution), and magnetic metal (2.7% Fe and Mn case) states. The complex dielectric function of transition metal atom substituted phosphorene was calculated by using linear response theorybased Kubo  greenwood formula, which manifests the energy band of solid and explains the various spectral knowledge. 

T00.00221: Higher Dimensional Spin Liquid on the Centred Pyrochlore Lattice Rajah P Nutakki, Lode C Pollet, Ludovic D Jaubert, Dirk Volkmer, Richard RoessOhlenroth, Alexander Tsirlin, Anton Jesche, Phillip Gegenwart, HansAlbrecht Krug von Nidda Magnetic systems on frustrated lattices have proven a fertile source for the discovery of exotic states of matter, from quantum spin liquids to spin ice. Typically, these frustrated lattices are constructed from triangular or tetrahedral clusters of three or four spins respectively. The metalazolate framework, [Mn(ta)_{2}], realizes a centred pyrochlore lattice, where the basic cluster is a centred tetrahedron of five magnetic ions. We study a relevant minimal Heisenberg model, finding a spin liquid in a large region of the phase diagram. Comparison to measurements of the magnetic properties of [Mn(ta)_{2}] indicates that the material is proximate to such a state. We propose an effective description of the spin liquid as a threedimensional slab of a Coulomb phase on a fourdimensional lattice, which rationalizes the low temperature correlations of the model for a large range of parameters. This introduces a novel lattice geometry within which to explore the rich physics of frustrated magnetism. 

T00.00222: Spin reorientation transition and rare earth ordering in Dy_{0.7}Er_{0.3}FeO_{3} single crystal Dhanpal Bairwa, Harikrishnan S Nair, Krzysztof Gofryk, Thomas W Heitmann, Suja Elizabeth Rare earth orthoferrites, RFeO_{3} are antiferromagnets with high transition temperatures (750 K620 K). They exhibit spin reorientation (SR), exchange bias, multiferroicity and magnetocaloric effects. In ErFeO_{3}, Fe^{3+} orders antiferromagnetically below 620 K and shows Γ_{4} (G_{x}, A_{y}, F_{z}) to Γ_{2} (F_{x}, C_{y}, G_{z}) SR transition between 80 K100 K, while in DyFeO_{3}, Fe^{3+} shows SR from Γ_{4} (G_{x}, A_{y}, F_{z}) to Γ_{1 }(A_{x}, G_{y}, C_{z}) near 35 K. Er^{3+} and Dy^{3+} ordering occurs below 1.3 K and 4 K respectively in ErFeO_{3} and DyFeO_{3}. Considering the different types of SR transition in Er and Dy ferrites, it would be interesting to study Er substituted DyFeO_{3}. Floatzone grown Dy_{0.7}Er_{0.3}FeO_{3} single crystals are characterized by XRD, neutron scattering, and magnetic susceptibility measured on oriented samples. We observe SR transition from Γ_{4} to Γ_{2} near 20 K and rare earth ordering near 3 K. 

T00.00223: Role of hightemperature Fe/MnEr antiferromagnetic exchange coupling in spin transport at single crystal ErFe_{0.55}Mn_{0.45}O_{3}Pt interface Priyanka Garg, Aditya A Wagh, Tirthankar Chakraborty, Suja Elizabeth, P S Anil Kumar A 3D AFM ErFe_{0.55}Mn_{0.45}O_{3} (T_{N} = 355 K) exhibits antiferromagnetic (AFM) exchange coupling and interesting interplay between Fe/Mn and Er sublattices in Γ_{4}(G_{x}, A_{y}, F_{z}) phase at room temperature (T). For instance, lowering the T (under H = 50 Oe) first results in compensation point (zero netmagnetization, M_{net}) near 266 K and then exhibits negative M_{net} down to 255 K where it transforms to Γ_{1}(A_{x}, G_{y}, C_{z}) phase. Application of magnetic field (H) in Γ_{4 }phase changes the spin moment configuration wherein, M_{net} and Neel vector G_{x} tend to align parallel and perpendicular to H, respectively. Inside Γ_{4} phase in ErFe_{0.55}Mn_{0.45}O_{3}, M_{net} is highly sensitive to the change in T and H. Here, we report spin Hall magnetoresistance (SMR) measurements carried out on bplate of single crystal ErFe_{0.55}Mn_{0.45}O_{3}Pt hybrid while rotating H in acplane. Our SMR studies in the Trange, 200 to 400 K probe Fe/MnEr AFM coupling, compensation point, negative magnetization and Hinduced flipping of the sublattices, revealing the key role of competing relative magnitudes of Fe/Mn and Er sublattices (i.e. M_{net}) in the spin transport. In summary, our spin transport investigations on ErFe_{0.55}Mn_{0.45}O_{3 }underline prospects of this 3D AFM material at room temperature for future AFM spintronic devices. 

T00.00224: Calibration of AC magnetometers for measuring magnetic fluid magnetization Zoe Boekelheide, Henry Steinthal AC magnetometers for characterizing magnetic nanoparticles in fluid are gaining popularity as the applications of magnetic nanoparticle fluids at AC frequencies, such as magnetic hyperthermia and magnetic particle imaging, expand[13]. One problem is the magnetization calibration of these magnetometers. There are practical constraints on the size and shape of the pickup coils, the vials containing fluid sample, and the nearuniform magnetic field region[2]. These constraints lead to a geometry in which the sample is too small to approximate as a long rod but too large for a pointdipole approximation[4]. We will present theoretical calibration factor calculations for these intermediate geometries along with experimental verification. In this geometry, the calibration factor is particularly sensitive to changes in the sample aspect ratio and distribution of magnetic moment within the sample, moreso than in [5]. Thus, samples that are inhomogeneous or in which evaporation occurs require additional calibration steps. 

T00.00225: Universal fluctuating regime in triangular chromate pure Heisenberg S=3/2 antiferromagnets Philippe Mendels, K. Somesh, Ramesh Nath, Alexander Tsirlin, Yuji Furukawa, Andrej Zorko, Gediminas Simutis, Fabrice Bert, N. Büttgen, Markus PrinzZwick We report xray diffraction, magnetic susceptibility, heat capacity, ^{1}H nuclear magnetic resonance (NMR), and muon spin relaxation (µSR) measurements, as well as bandstructure calculations for the frustrated S = 3/2 triangular lattice Heisenberg antiferromagnet (TLHAF) αHCrO_{2} (trigonal, space group: R3m). The intralayer and interlayer couplings are estimated to be J/k_{B} ≈ 24 K and J’/k_{B} ≈ 2.8 K, respectively. This compound undergoes a clear magnetic transition at T_{N} ≈ 22.5 K, as seen from the drop in the muon paramagnetic fraction and concurrent anomalies in the magnetic susceptibility and specific heat capacity. Local probes (NMR and µSR) reveal a broad regime with slow fluctuations down to 0.7 T_{N}, this temperature corresponding to the maximum in the µSR relaxation rate and in the NMR wipeout. The scaling of the NMR and µSR data with respect to J or T_{N} supports a scenario where a crossover from 2D to 3D correlations sets in around 0.7 T_{N} preceded by a typical 2D regime of the TLHAF. From the comparison with NaCrO_{2} and αKCrO_{2}, the fluctuating regime and slow dynamics below T_{N} appear to be hallmarks of the TLHAF with ABC stacking. We discuss the role of interlayer frustration which may bear implications to recent spinliquid candidates with the triangular geometry. 

T00.00226: Superparamagnetic Tunnel Junctions with Nanosecond Relaxation Time for Probabilistic Computing Shun Kanai, Keisuke Hayakawa, William A Borders, Takuya Funatsu, Butsurin Jinnai, Junta Igarashi, Hideo Ohno, Shunsuke Fukami Recently, superparamagnetic tunnel junctions (sMTJs) with a low barrier energy have been shown to compose probabilistic bits (pbits) for probabilistic computing using 300 times fewer transistors and consuming onetenth of the operating energy than purely CMOSbased pbits [1]. Here we investigate the timedomain response of sMTJs, which characterizes an average switching event time (the relaxation time) between bit states, and affects the computation time. Based on an analysis of the time evolution of entropy for the magnetization direction probability distribution, we propose that for shorter relaxation times, it is necessary not only to reduce the barrier energy but also to increase the precession frequency [2]. According to this design guideline, sMTJs with inplane magnetic easy axis are fabricated and achieve relaxation times down to 8 ns [3], which is more than 5 orders of magnitude shorter than that of typical sMTJs with perpendicular easy axis [1]. 

T00.00227: Characterization of magnetic mutual couplings in 2D arrays of magnetic tunnel junctions Yiou Zhang, Shiyu Zhou, Gang Xiao In array of magnetic tunnel junctions (MTJs) or magnetic sensor composing multiple MTJ elements, magnetic coupling between MTJ elements emerge from the stray field of the magnetic free and pinned layers. Understanding the coupling is important for applications in magnetic imaging and in spintronic devices. Such mutual coupling, particularly for small element separation, undesirably increases the noise level in the MTJ elements and limits the MTJ element separation. MTJ with a vortex magnetization (vortex MTJ), with no stray field from the free layer, is one solution to reduce the magnetic couplings. In this work, we have performed a comprehensive characterization of the magnetic coupling between tightly spaced vortex MTJ elements, through measuring their cross correlation under various external magnetic field. No magnetic coupling between the free layers of MTJ elements have been found. Nevertheless, coupling between the magnetic pinned layer of one vortex MTJ and free layers of its neighbors has been observed. Such interlayer coupling not only sets a fundamental limit of MTJ element separation, but also implies additional noise source in MTJ sensors. Our work would provide important insights into improving noise level and spatial resolution of MTJbased magnetic sensor arrays. 

T00.00228: Effects of alternating forces in domain wall roughness Nirvana Caballero With a GinzburgLandau model that can be reduced to the quenched EdwardsWilkinson equation, I show how it is possible to numerically emulate an experimental protocol used to probe the effects of alternating magnetic fields in ferromagnetic domains. The model allows me to capture the main experimental results: under constant field pulses only favoring domain growth or shrink, the domain wall roughness exhibits a powerlaw behavior described by the KardarParisiZhang (KPZ) exponent. When instead domain walls are subjected to alternating fields favoring domain growth and shrink subsequently, the exponent in the roughness is increased. I explain this effect by arguing that under alternating fields the disorder correlation length felt by the domain wall is increased, thus pushing the region in which the KPZ exponent is observed towards larger scales. When the disorder correlation length is increased, one has access to an intermediate excess powerlaw with exponent 0.9 that emerges as a consequence of the microscopic interplay between disorder and thermal effects. 

T00.00229: Effects of array shape and disk ellipticity in dipolarcoupled magnetic metamaterials Sam Sloetjes, Einar Digernes, Anders Stromberg, Fredrik K Olsen, Ambjoern Bang, Alpha T N'Diaye, Rajesh V Chopdekar, Erik Folven, Jostein K Grepstad Twodimensional lattices of dipolarcoupled thin film ferromagnetic nanodisks can give rise to emergent ‘superferromagnetic’ (SFM) order when the spacing between dots becomes sufficiently small. This allows for the design of metamaterials, which can be tailored to have a specific type of longrange order magnetic order by tuning the lattice symmetry. We have previously shown experimentally that a square lattice symmetry gives rise to antiferromagnetic order, and a hexagonal lattice gives rise to ferromagnetic order. In the present study, we pattern the arrays into micron sized hexagons, squares, and rectangles in order to investigate shape anisotropy as an effect of the finitesize for such arrays. The magnetic domain patterns were examined using XPEEM and were found to be below their blocking temperature at room temperature. Due to lithographic defects, the dots were found to feature a slight ellipticity, thus giving rise to a shape anisotropy that overwhelmed the anisotropy of the array shape. Distinct differences were found in the magnetic switching characteristics of horizontally and vertically oriented rectangular arrays which was corroborated by micromagnetic simulations. 

T00.00230: Reaching the equilibrium spin structure of Ca_{3}Co_{2}O_{6} Ising triangular frustrated magnet at low temperatures Ivan Nekrashevich, Xiaxin Ding, Fedor F Balakirev, Hee Taek Yi, SangWook Cheong, Leonardo Civale, Yoshitomo Kamiya, Vivien Zapf Understanding the observed metastable magnetization steps vs magnetic field with very slow dynamics in Ca_{3}Co_{2}O_{6} Ising triangular frustrated magnet poses a longstanding challenge. We make a step forward in solving this puzzle by conducting a detailed study of the ground state of this spin system in temperatures below 4 K. Our work shows that the ground state can be reached at low temperatures by cooling down Ca_{3}Co_{2}O_{6} single crystal in fields ranging from 0.125T to 3.6T oriented parallel to its easymagnetization axis. Through this procedure we achieve a predicted ground state at 2 K and explore stability of this state by timerelaxation measurements. We do not however succeed in approaching the ground state with quantum annealing in transverse magnetic fields of up to 7 T, likely due to the large Ising anisotropy of the Co spins. We compare our equilibrium experimental data for Ca_{3}Co_{2}O_{6} spin system to the quantum Monte Carlo simulations of a modified version of the Axial NextNearestNeighbor Ising (ANNNI) model. This modified ANNNI model is derived for Ca_{3}Co_{2}O_{6} by interleaving three chains to form one effective spin chain with frustrated nearest, nextnearest and nextnextnearest neighbor interactions. 

T00.00231: StrainControlled Atomic Scale Distortions and AntiFerromagnetism at LaFeO3/SrTiO3 Interface Menglin Zhu, Jose Flores, Joseph A Lanier, Sevim Polat Genlik, Maryam Ghazisaeidi, Fengyuan Yang, Jinwoo Hwang Antiferromagnetic insulators have gained attention due to low loss, fast switching, and potential for nextgeneration spintronics applications. To achieve this, understanding the process of switching and control of magnetic properties via external stimuli, such as strain and applied fields, needs to be established. We report notable changes in magnetic canting in antiferromagnet LaFeO_{3} thin films grown on SrTiO_{3}, which originates from the changes in the lattice distortion at the interface. Atomicscale scanning transmission electron microscopy (STEM) reveals that the rotation of FeO octahedra changes within the first ~ 5 orthorhombic unit cells, with both the inplane and outofplane rotations, progressively decreasing near the interface. Cation (La) positions are also affected by the strain at the interface, showing less distortion due to the connection to the cubic SrTiO_{3}. Nanoscale structural domains were also observed, and they are connected to the formation of magnetic domains near the interface, which we directly image using Lorentz TEM. Based on the experimental results, density functional theory calculation is performed to help elucidate the exact mechanism of the observed structureproperty relationship. 

T00.00232: Emergent Moments and Random Singlet Physics in a Majorana Spin Liquid Sambuddha Sanyal, Kedar Damle, John T Chalker, Roderich Moessner We exhibit an exactly solvable example of a SU(2) symmetric Majorana spin liquid phase, in which quenched disorder leads to randomsinglet phenomenology of emergent magnetic moments. More precisely, we argue that a strongdisorder fixed point controls the low temperature susceptibility χ(T) of an exactly solvable S=1/2 model on the decorated honeycomb lattice with vacancy and/or bond disorder, leading to χ(T)=C/T+DT^{α(T)−1}, where α(T)→0 slowly as the temperature T→0. The first term is a Curie tail that represents the emergent response of vacancyinduced spin textures spread over many unit cells: it is an intrinsic feature of the sitediluted system, rather than an extraneous effect arising from isolated free spins. The second term, common to both vacancy and bond disorder [with different α(T) in the two cases] is the response of a random singlet phase, familiar from random antiferromagnetic spin chains and the analogous regime in phosphorusdoped silicon (Si:P). 

T00.00233: Charge Transfer and Defects in Ultrathin Metal Oxide – Graphene Spintronic Interfaces Daria Belotcerkovtceva, Renan Marcel, Elin Berggren, R. R. Maddu, Tapati Sarkar, Yaroslav O Kvashnin, Andreas Lindblad, Olle Eriksson, M. Venkata Kamalakar The way metal oxides layers interface with graphene determines the performance of graphene spintronic devices. Titanium and Aluminumbased oxides are two widely used tunnel barriers in such devices at the contacts, and the impact of ultrathin metal oxide layers on graphene in electrical and spin transport properties and spin relaxation in graphene remains unclear. While it is believed that Aloxide exhibits pinholes that lead to spin relaxation at contact interfaces, using Tibased tunnel barriers, ns spin lifetimes are observed^{1,2}. In this work, we investigate the influence of TiO_{x} and AlO_{x} ultrathin layers on graphene via electrical measurement, structural and spectroscopic techniques, and theory. We observe that both oxides layers lead to ptype doping in graphene, with atomic force microscopy revealing distinct coverage and topographic features. While surface charge transfer occurs in both cases, in sharp contrast to TiO_{x}, the AlO_{x}graphene samples show the emergence of sp^{3} defects as revealed by Raman spectroscopy and confirmed by Xray photoelectron spectroscopy. Our electronic structure calculations suggest interface configurations that match the charge transfer and defect emergence at these metaloxidegraphene interfaces. This study concludes that while ultrathin TiO_{x} on the top of graphene involves charge transfer doping, however, at the AlO_{x}Graphene interface, a combination of charge transfer and defect doping occurs that can explicate the implications to electrical and spin transport across such interfaces. 

T00.00234: Effect of Hubbard U on Calculations of Magnetic Properties of α″–Fe_{16}N_{2} Peter Stoeckl, Przemyslaw W Swatek, JianPing Wang The ordered iron nitride phase α″–Fe_{16}N_{2} has long been a candidate giant saturation magnetization material, but firstprinciples electronicstructure calculations have struggled to reproduce recent observations of high magnetic moment, while calculations of magnetocrystalline anisotropy (MCA) vary significantly. Within the framework of densityfunctional theory (DFT), a common extension to the usual generalizedgradient approximation (GGA) exchangecorrelation (XC) functional is the inclusion of Hubbard parameters U (,J) as GGA+U. A number of previous papers have applied this method to Fe_{16}N_{2}, each with their own choice of Hubbard parameters. 

T00.00235: Electric field control of structural, magnetic and transport properties of shape memory alloys: NiMnIn thin films at room temperature Ahmad M Alsaad The goal of this work is to demonstrate a new family of nanoferroic multifunctional devices, based on shapememory Heusler alloy films in ferroelectric heterojunctions, where resistance, magnetic and structural properties of the Heusler alloys will be switchable by applied electric field. Heusler alloys are a group of intermetallic compounds that have unique and interesting electromagnetic behaviors, including the magnetic shapememory effect. Selected shapememory Heusler alloys are expected to be better than manganitebased compounds because their transformations can be controlled to occur near room temperature. This research attempts to distinguish the roles of electronic and strainmediated coupling between layers in heterojunctions in order to determine the origin of each effect. It also attempts to identify the mechanism of the martensitic phase transformation in the Heusler alloy films. It is ultimately envisioned that this research may lead to a new class of nanoferroic multifunctional devices enabling new sensor and electronic applications. These devices will have a potential for use in memory, sensors and magnetic refrigeration. 

T00.00236: Paving the way for Boolean logic by skyrmion based programmable logic devices Mehmet Cengiz Onbasli, Arash Mousavi Cheghabouri Skyrmions enable ultralowpower nonvolatile logic gate designs because of their nanoscale dimensions, currentdriven motion, and topological protection. The logic inverter (NOT) gate is an important component in digital spintronics employing skyrmions. Despite recent computational and practical demonstrations, a skyrmionbased lowpower, wideband, and cascadable inverter gate is yet to be developed. The systematic design and analysis of an inverter gate is critical for scalable skyrmionbased logic circuits. Here, we demonstrate that the inverter gate can operate with direct current drive, wide bandwidth, low energy consumption (~1350 k_{B}T/bit at room temperature), small footprint (~300 nm) with dimensions feasible for nanofabrication, no or very limited external magnetic field, cascadability and room temperature thermal stability. 2D room temperature semiconductor or insulating magnetic materials could also help eliminate Joule dissipation. These findings imply that the inverter gate might be cascaded and operated without loading or thermal drift inside largerscale digital spintronic circuits. By combining the inverter with AND and OR gates in a similar functional, thermally robust, and cascadable way, any arithmetic or Boolean logic capabilities may be implemented. 

T00.00237: Optimized Magnetization Dynamics in Magnonic Nanograting Filters Mehmet Cengiz Onbasli, Rawana Yagan, Ferhat Katmis Onchip integration for compact microwave data communication, data storage, and information transfer in ferromagnetic waveguides might be enabled by spin signal processing in the GHz bands, such as filtering, frequency multiplication, and excitation. On the nanoscale, magnonic crystals (MCs) might be used to construct many of these functions inside the same physically defined structure. MCs and gratings could enable tunable spinwave filters, logic, and frequency multiplier devices. We explore the impact of nanowire damping, excitation frequency, and geometry on the spin wave modes, spatial and temporal transmission profiles, and external current and magnetic fields for finite patterned nanogratings. Higher frequency spin wave modes are transmitted with higher intensities when the nanowire is stimulated by stronger external RF fields. Changing the width, pitch, and number of periods of a nanowire grating can assist shift transmitted frequencies throughout the super highfrequency range. In magnetic nanowires, our approach might allow for spinwave frequency multipliers, selective filtering, excitation, and suppression. Our work might shed light on magnon dynamics and spectral features in thin film MCs. 

T00.00238: Nanooptical imaging of localization phenomena in lowangle twisted bilayer graphene. Andreij Gadelha We present evidence for lattice localization physics in the novel reconstructed twisted bilayer graphene (rTBG) system. Here, two graphene layers with an angle smaller than one degree produce the rTBG. In this condition, the carbon atoms rearrange, forming triangular structures composed of solitons and topological points. We use nanoRaman spectroscopy, where a visiblelight laser beam is focused on a nanoantenna, to image the rTBG structure. In addition to the first crystalline structure visualization by visible light, this technique provides indepth spectroscopic information of the rTBG system. Thus, we observe the manifestation of the nonconventional localization of phonons and the already predicted electronic localization. Besides, we also illustrate that the electronphonon coupling in this system is unique, and its understanding can help elucidate the magicangle superconductivity. Therefore, our work unravels fascinating phenomena in the fastdeveloping twistronics field. 

T00.00239: Twist dependent spin resolved conductance in GraphenehBN van der Waals heterostructure Shivani Rani Graphenehexagonal boron nitride van der Waals heterostructures are close to ideal systems for nanoelectronic and spintronic applications. In particular, such heterostructures are considered ideal for achieving high spin accumulations in graphene, an unprecedented material for efficient spin communication. In this paper, we unravel how the efficiency of spin injected charge carriers have changed by twisting the hBN barrier interfacing with graphene and Ferromagnetic lead of Ni(111)/Co(111). Through Firstprinciples calculations, we show that spinup and spindown electrons exhibit remarkably distinct conductivities leading to a high modulation of spin injection in both magnitude and sign as orientation changes. Our results suggest that for nanoscopic contacts, the magnitude and sign of spin injection efficiency are highly dependent upon twists between graphene and hBN lattices and it is possible to reach a high ~67%, even utilizing singlelayer hexagonal boron nitride by manipulating the angle between graphene and hexagonal boron nitride. Most negative spin polarization ~`90% is achieved due to trilayer of hBN using Co(111) electrode. Our calculations provide a guideline to engineer van der Waals heterostructure for efficient future spintronic devices. 

T00.00240: RealSpace Observation of StrainInduced Dynamics of Magnetic Skyrmions at Room Temperature. Chen Liu Magnetic skyrmions which are swirling nanometric spin textures with nontrivial topology have been widely researched in the past decades. The ability to manipulate skyrmionic spin configurations and drive them to move via a mechanical strain is not only promising for developing lowconsuming spintronics devices but also inherently attractive for the resulting exotic physics. Despite recognition of the potential, its experimental realization has remained challenging. Here, we have experimentally observed the straininduced motion of skyrmions at room temperature in real space. We demonstrate that the motion of both isolated skyrmion and skyrmion lattices can be easily driven by a uniaxial compressive strain. Moreover, the strain rate also plays an essential role during the process. 

T00.00241: Abstract Withdrawn


T00.00242: Engineering the spin conversion in graphene monolayer epitaxial structures JuanCarlos RojasSanchez, Alberto Anadon, Adrián Gudín, Ruben Guerrero, Iciar Arnay, ALEJANDRA GUEDEJAMARRON GIL, Pilar Jiménez, Jose Manuel Díez Toledano, Fernando Ajejas, María Varela, Sebastien PetitWatelot, Irene Lucas, Luis Morellón, Pedro Antonio Algarabel, Manuel Ricardo Ibarra, Rodolfo Miranda, Julio Camarero, Paolo Perna Heavy metals (HMs) and interfaces with spin texture are employed to get a large spintocharge conversion^{1}. Graphene in proximity with those systems has been proposed as an efficient and tunable spin transport channel. We explore the role of a graphene monolayer (Grm) between Co and HM. The Co/Grm/HM stacks have been prepared on epitaxial Ir(111) structures grown on sapphire crystals, in which the spin detector (topHM), and the spin injector (Co) are all grown insitu under controlled conditions and present clean and sharp interfaces. We find that an intercalated Grm effectively reduced the spin current injected into the HM from the bottom Co layer. This has been observed by detecting a net reduction of the sum of the spin Seebeck and interfacial contributions due to the presence of Grm and independently from the spin Hall angle sign of the HM used^{2}. 

T00.00243: Magnetism and electronic band structure of FeCrV_{1x}Co_{x}Al Parashu R Kharel, Jax Wysong, Gavin Baker, Lukas Stuelke, Shah Valloppilly, Paul Shand, Pavel Lukashev Heusler alloys have attracted much attention because of their multiple interesting properties with prospects for spintronics, energy technology and magnetic refrigeration. Additionally, the magnetic properties of these materials can be tuned to fit specific applications by adjusting the elemental composition. We have synthesized FeCrV_{1x}Co_{x}Al Heusler alloys having potential for spintransport based applications using arc melting and highvacuum annealing. The room temperature xray diffraction patterns of the asprepared FeCrCoAl, FeCrCo_{0.5}V_{0.5}Al and FeCrVAl indicate that all three samples crystallize in cubic structure without secondary phases. The asprepared FeCrCoAl alloy shows a ferrimagnetic order with a high Curie temperature of about 450 K but both FeCrCo_{0.5}V_{0.5}Al and FeCrVAl show paramagnetic behavior. In this presentation, we will discuss the effect of heat treatment on the structural and magnetic properties of FeCrV_{1x}Co_{x}Al and also the results of our first principle calculation. 

T00.00244: Solving Electron Spin DriftDiffusion Equations in Presence of Hyperfine Interactions Dana Coleman, Bryan Stevens, Truman Schulz, Nicholas J Harmon Large nuclear fields, induced by the hyperfine interaction, are known to influence spin transport characteristics in nGaAs [1,2,3]. Nuclear fields are added to the spin driftdiffusion equation and the resulting spin distributions are calculated. Various boundary conditions are assumed in order to model various experimental arrangements. Due to the complicated nature of the nuclear field, the steady state spin driftdiffusion equations are nonlinear and must be solved numerically. In this work, we examine solutions for the spin distribution and spin current in the presence of a nuclear field. Lastly, the effect of magnetic field gradients on steady state spin are explored to show how these gradients affect spin current. 

T00.00245: Plaquette crystal order in the triangularlattice J_{1}J_{2} Heisenberg antiferromagnet and related models William Holdhusen, Abhishek Kumar, Babak Seradjeh, Philip Richerme, Gerardo Ortiz The triangularlattice Heisenberg antiferromagnet (TLHA) is a deceptively simple model exhibiting rich physics, especially with the addition of nextnearestneighbor (J_{2}) couplings. Although the decadeslong debate as to the nature of the J_{2}=0 ground state has largely been settled in favor of a canted Néel order, the seemingly disordered intermediate phase arising around J_{2}=1/8 is still poorly understood, with conventional numerical methods giving ambiguous and conflicting results. To bring new insight to this problem, we apply hierarchical meanfield theory (HMFT). HMFT has been successfully applied to a number of related frustrated magnetic systems, most relevantly the square lattice Heisenberg antiferromagnet. Inspired by analysis of HMFT solutions on a number of clusters preserving and breaking specific symmetries of the TLHA, we develop a parameter indicating plaquettecrystal order in the intermediate phase. To better understand this phase, we also examine its stability as the ZZ interactions are tuned to zero (giving the XY model) and in the presence of thirdnearest neighbor interactions. 

T00.00246: Phase transition and large caloric effect in multicomponent intermetallics Jacob Casey, Mahmud Khan, Arjun K Pathak Materials that exhibit a firstorder phase transition in response to varying temperature, magnetic field, or pressure are of great interest for basic and applied science. Particularly, multicomponent intermetallics are the foundation of a vast basic science playground, where compounds with firstorder phase transition could show multifunctionality, including large magnetocaloric, shape memory, and unusual magnetotransport phenomena. In this presentation, we will present the phase transition, magnetic and magnetocaloric effect of multicomponent highentropy type multicaloric alloys that constitute abundant and nontoxic elements. Microstructural manipulations, phase stability, and compositional engineering to tune the phase transitions, magnetic and caloric properties of these materials will be discussed. 

T00.00247: Understanding the importance of local magnetic moment in FeSe monolayer Sudip Pokharel Local magnetic moment (LMM) and antiferromagnetic (AFM) fluctuation play a critical role in affecting the properties of FeSe superconductor. By constraining the local magnetic moment on Fe atoms using density functional theory, we investigate how LMM in FeSe monolayer alters the total energy, heights of Se atoms, band structure, and the electronic properties, for three different AFM spin arrangements which consist of the checkerboard (CB), collinear (CL), and paircheckerboard (PC) spin phases. We find that (i) the total energy decreases drastically in all three spin structures when LMM develops, showing that the existence of LMM significantly stabilizes the system. The optimal LMM is found to be 2.23 m_{B}, 2.54 m_{B}, and 2.47 m_{B} respectively in the CB, CL, and PC spin phases. (ii) The heights of Se atoms increase markedly (and in a quadratic manner) with LMM, demonstrating a strong magnetostriction effect. Also intriguingly, we find that the Se heights are insensitive to spin ordering, displaying a rather universal dependence on LMM in three different AFM spin phases. (iii) LMM is shown to alter substantially the electron band structures and Fermi surfaces. Near their optimal LMM, while both CB and PC phases possess electron pockets and no hole pockets, the CL phase exhibits neither electron pockets nor hole pockets, and interestingly, it becomes a semiconductor of a small gap of 60 meV. These results reveal that there is a rich and interesting physics to be tuned by LMM in FeSe superconductor. 

T00.00248: Nonclassical orbital magnetism in ultrathin transition metal films Joshua Peacock Fe, Co, and Ni are the "classical" transition metal ferromagnets usually described in terms of the Stoner or CurieWeiss model of magnetism. We utilize anomalous Hall effect (AHE) measurements to demonstrate that as a function of temperature T, ultrathin films of Co/Ni exhibit two phase transitions at Tc1 and Tc2>Tc1. The transition at Tc1 is identified as the onset of the usual spin ferromagnetism. The transition at Tc2, in the paramagnetic spin state, is characterized by the opposite sign of AHE, and the corresponding order parameter freezes out above Tc2 before the corresponding symmetrybroken state becomes stable. We analyze the dependence on the field direction, the relative thicknesses of Co and Ni, dc and microwave electric current, and magnetooptic response to show that the transition at Tc2 is associated with the onset of a metastable orbitallyordered state of 3d electrons. This state is nonclassical, it cannot have inplane magnetic components, and does not exhibit precessional dynamics. Calculations based on the Hubbard model accurately reproduce the observed effects. Our results shed light on the mechanisms of magnetism in multiorbital systems and other electron correlation effects including unconventional superconductivity. 

T00.00249: Topology of a Driven 2D Spin Torque Oscillator Array Shivam Kamboj, Hilary M Hurst Arrays of spin torque oscillators (STO) provide a platform to study dissipative systems, which can be described by a nonHermitian effective Hamiltonian. In this research project, we examine how a 2D array of STOs can be mapped to a 2D extension of the nonHermitian SSH Model. We examine the energy spectrum by both analytical and numerical computation of the effective Hamiltonian. We examine the symmetries of the Hamiltonian and discuss how they affect the existence of edge states. Tuning the Gilbert damping or the injected spin current in the model allows us to explore the topology of the system under different parameter regimes. In this model, the edge states correspond to autooscillation of edge STOs while bulk oscillators do not activate. This research emphasizes the broader impacts of nonHermitian topology in spintronic devices by exploring the possibility of real spintronic devices with nontrivial topology. With the successful completion of this research project energy dissipation in spintronic devices can be minimized; topologically protected edge states can act as a conducting channel for spin on the edges while at the same time the bulk remains nonconducting. 

T00.00250: Gatetunable magnetism via resonant Sevacancy levels in WSe_{2} Dung Nguyen Tuan The confined defects in twodimensional van der Waalslayered semiconductors can be easily tailored using charge doping, strain, or an electric field. Nevertheless, gatetunable magnetic order via intrinsic defects has been rarely observed to date. Herein, we report a gatetunable magnetic order via resonant Se vacancies in WSe_{2}. The Sevacancy states were probed via photocurrent measurements with gating to convert unoccupied states to partially occupied states associated with photoexcited carrier recombination. The magnetophotoresistance hysteresis was modulated by gating, which is consistent with the density functional calculations. The two energy levels associated with Se vacancies split with increasing laser power, owing to the robust Coulomb interaction and strong spin–orbit coupling. Our results offer a new approach for controlling the magnetic properties of defects in optoelectronic and spintronic devices using van der Waalslayered semiconductors. 

T00.00251: Spinselective holeexciton coupling in Vdoped WSe_{2} ferromagnetic semiconductor at room temperature Lan Anh Nguyen Thi While valley polarization with strong Zeeman splitting is the most prominent characteristic of twodimensional (2D) transition metal dichalcogenide (TMD) semiconductors under magnetic fields, enhancement of the Zeeman splitting has been demonstrated by incorporating magnetic dopants into the host materials. Unlike Fe, Mn and Co, V is a unique dopant with distinctive features of ferromagnetic semiconducting properties at room temperature with large Zeeman shifting of band edges. Nevertheless, little known is the excitons interacting with spinpolarized carriers in Vdoped TMDs. Here, we report anomalous circularly polarized photoluminescence (CPL) in a Vdoped WSe_{2} monolayer at room temperature. Excitons couple to Vinduced spinpolarized holes to generate spinselective positive trions, leading to differences in the populations of neutral excitons and trions between left and right CPL. Using transient absorption spectroscopy, we elucidate origin of excitons and trions that are inherently distinct for defectmediated and impuritymediated trions. Ferromagnetic characteristics are further confirmed by the significant Zeeman splitting of nanodiamonds deposited on the Vdoped WSe_{2} monolayer. Our findings open a venue of 2D vdW semiconductors for future lowpower optospintronics. 

T00.00252: Ferromagnetic Clusters and High Magnetocrystalline Anisotropy in Co_{3}Sn_{2}S_{2} Vipin Nagpal, Sudesh Bhalothia, Satyabrata Patnaik Cobaltbased sulphides with formula Co_{3}A_{2}S_{2} (A = Sn and In) are strongly correlated electron systems that have triggered an immense research interest for their remarkable properties. Herein, the anisotropic magnetic properties of single crystals of a ferromagnet Co_{3}Sn_{2}S_{2} are investigated in the presence of magnetic field H applied along caxis (H  c) and abplane (H  ab). A glasslike magnetic behaviour is revealed at low temperatures in magnetization. The inverse susceptibility measurements exhibit a sharp downturn and nonlinear behaviour close to critical temperature T_{C} in the paramagnetic region signifies the presence of shortrange ferromagnetic clusters above T_{C} and strong Griffiths singularity in Co_{3}Sn_{2}S_{2}. The magnetic hysteresis loops indicate the shortrange magnetic correlations and the hard and soft magnetic phases of Co_{3}Sn_{2}S_{2}. The Takahashi’s spin fluctuation theory analysis provides sufficient evidence for itinerant ferromagnetism in Co_{3}Sn_{2}S_{2}. A large magnetocrystalline anisotropy accompanied by a high anisotropy field implies the strong spinorbit coupling phenomenon. Our results emphasize an intuitive understanding of the complex magnetism in Cobased systems. 

T00.00253: Mangetotransport properties of polycrystalline Fe_{2}MnSn thin films Duston Wetzel, Yub Raj Sapkota, Dipanjan Mazumdar If fully spinbased consumer electronics are ever to be realized, the separation and manipulation of electronic spin must be mastered. To this end, many exotic materials with novel electronic and magnetic properties have recently been theoretically modeled and experimentally studied, some of which show great potential applicability in sensing and memory. One promising set of such materials are Manganesebased Heusler compounds, which exhibit high spin polarization, low saturation magnetization, magnetic anisotropy, and high Curie temperatures Tc. In this work, magnetotransport properties of largearea magnetron sputtered thin films of polycrystalline hexagonal (D0_{19}) Fe_{2}MnSn and related Hueslerlike Mn_{3x}Fe_{x}Sn compounds are presented, including the longitudinal, transverse, and angular dependent room temperature magnetoresistance, as well as temperature dependent magnetization and Hall measurements. Our preliminary results deomonstrate a crossover effect from GMRtype behavior to AMR with increased bias voltage. 

T00.00254: Magnomechanics in a suspended beam Harshad Mishra, Kalle S. U. Kansanen, Camillo Tassi, Mika Sillanpaa, Tero T Heikkila Cavity optomechanical systems have long been the preferred system for studies investigating the interactions between photons and mechanics. However, their structural configuration limits the possibility to integrate multiple systems into a single chip. Our work is focused towards establishing magnomechanical analogies to optomechanics, where the electromagnetic cavity is replaced by the ferromagnetic resonance in a magnetic film. Our theoretical calculations demonstrate the existence of a coupling between the mechanical and the magnetic modes in the beam in the presence of an initial static deformation, which is due to a mismatch of the elastic coefficients and deposition induced strains. The experimental structure is a suspended bilayer beam of CoFeB (50 nm) and Al (100 nm) such that the mechanical as well as the magnetic modes can be excited individually. We measure the mechanical sideband around the Kittel frequency for different magnetic fields as well as for constant beam displacements and demonstrate the magnon – mechanical coupling. 

T00.00255: General Framework for the Determination of Magnetic Exchange Constants for Transition Metal Oxides from FirstPrinciples Calculations Guy C Moore Moving from the atomistic picture of magnetism to larger length scale models is an important challenge for the design and discovery of promising candidates for material science and physics. This problem requires increased computational demand and care for correlated electron systems, such as transition metal oxides, in which multibody interactions are difficult to model using conventional Kohn–Sham density functional theory (DFT). In this study, we present a framework for obtaining magnetic exchange constants from DFT+U+J using the established singleparticle Green’s function approach, which can be used to study finitetemperature behaviour of lattice models using Monte Carlo methods, namely paramagnetic phase transitions. The Heisenberg exchange constants are highly sensitive to two important prerequisites: the magnetic groundstate, as well as the Hubbard U and Hund J values in DFT+U+J, which parameterize onsite corrections to coulomb interactions between localized electrons. We explore the sensitivity of the magnetic ground state and resulting exchange constants to U and J values. These Hubbard U and Hund J values are computed using the linear response formalism suitable for high throughput DFT applications. This computational approach will allow for the discovery of magnetic materials with technological applications ranging from spintronics to costeffective magnetocaloric materials for magnetic refrigeration. 

T00.00256: Doping Dependent Coercive Field in the Reduced Dimensional System La_{1x}Sr_{x}MnO_{3} (0 ≤ x ≤ 0.5) Thomas M Pekarek, Charles Bryant, Rodolfo Marquez Tavera, Dakota T Brown, James A Payne, Maitri P Warusawithana We have investigated the electronic and magnetic ground state of a series of La_{1−x}Sr_{x}MnO_{3 }thin films as a function of doping, x, for 0≤x≤0.5. The films were grown by molecularbeam epitaxy, epitaxially strained to (001) oriented strontium titanate substrates. We find that the ground state of these crystalline thin films is, in general, consistent with that observed in both bulk and thin film samples synthesized under a multitude of techniques. Our systematic study also reveals subtle features in the temperature dependent electronic transport and magnetization measurements that may correspond to JahnTeller type distortions in the lattice as a function of doping and temperature. The doping dependent coercive filed in this series was investigated in this context. 

T00.00257: Calculations of the lifetime of magnetic skyrmions and antiskyrmions in discrete systems with large number of spins Hannes Jonsson Topological stabilization of magnetic skyrmions is investigated for discrete 2D systems with ferromagnetic ground state. While a skyrmion is topologically protected in a continuous system, this is not so for discrete systems and the question is what limit is reached for a discrete system as the lattice constant becomes infinitesimal. Calculations of the skyrmion lifetime within harmonic transition state theory [1] are performed as a function of lattice constant [2]. The parameters of the Hamiltonian, i.e exchange (J) and anisotropy (K) and DzyaloshinskyMoriya (D) parameters, are chosen to keep the size of the skyrmion and its energy unchanged for sufficiently small lattice constants, in all cases consistent with a skyrmion in a given continuous micromagnetic model. The number of magnetic moments is over a million for the finest lattice. The energy barrier for skyrmion collapse in the limit of infinitesimal lattice constant approaches the value corresponding to the minimum energy of the BelavinPolyakov topological soliton. The entropy contribution to the preexponential factor in the Arrhenius expression for the skyrmion lifetime also approaches a constant. The lifetime, therefore, reaches a finite value in the limit of infinitesimal lattice constant [2]. Secondly, calculations are presented for large antiskyrmions in MnPtSn tetragonal Heusler material [3]. The calculations involve nearly a million spins and the parameter values in the extended Heisenberg Hamiltonian are chosen to reproduce experimental observations, in particular the 150nm diameter. The calculated lifetime is consistent with the reported laboratory observations and this exceptional stability at room temperature is found to result from large activation energy for collapse due to strong exchange coupling while the preexponential factor in the Arrhenius expression has a typical value. The long lifetime is, therefore, found to result in this case from energetic rather than entropic effects. 

T00.00258: Robust Magnetic Tunnel JunctionBased Molecular Spintronics Devices for Harnessing Molecular Quantum Properties Bishnu R Dahal, Eva Mutunga, Hayden Brown, Joshua Dillard, Pawan Tyagi Molecule are the smallest massproducible nanostructure with exotic quantum properties. Harnessing them as the device element has been focus of research for >70 years. However, conventional methods of connecting molecules with the two metal electrodes produce low yield and very limited in scope. This talk will discuss our magnetic tunnel junction based molecular device (MTJMSD) approach as a solution to many longstanding fabrication challenges. Here, we report fabrication process to realize robust crossjunction shaped MTJMSD where the minimum gap between the two ferromagnetic electrodes is tailored with the help of alumina insulatoralong the two exposed side edges. Molecules of interest are bridged across the insulating gap to serve as the dominant spin channels. Two exposed side edges are produced using liftoffmethod and has been discussed elsewhere. MTJMSD's robustness critically depend on the quality of insulating tunnel barrier. We have systematically optimized several factors using multiple Taguchi Design of Experiment approach. For this study optimized sputtering process parameters such as RF sputtering power, gas pressure, argonoxygen gas ratio, etching parameters. We successfully produced >95% yield of robust ~4 nm tunnel barrier with 2040 nA tunneling current at 100 mV to serve as testbed for MTJMSD realization. 

T00.00259: MAGNETISM


T00.00260: Lanthanoid photoelectron spectroscopy in Ln_{10}S_{14}O oxysulfides as a probe of covalency and chemical composition Brian A Wuille Bille, Jesús Velázquez Rareearth oxysulfides have been studied in a wide range of applications due to their multiple optoelectronic properties arising from their abundant excited electronic energy levels. Herein, we present the solidstate synthesis and systematic analysis of the lanthanoid (Ln) 3d Xray photoelectron absorption region for the early lanthanoid oxysulfides Ln_{10}S_{14}O (Ln = La, Ce, Pr, Nd and Sm). The multiplet structure is estimated to originate in the excitation of 3d electrons in addition to a ligandtometal charge transfer process, for both 3d_{5/2} and 3d_{3/2} photoelectron regions. As the atomic number, and 4f electron count, increases from Ce to Sm, the satellite and 3d signal energy separation tends to decrease for the same ligand environment, in conjunction with an increase in the 3dtosatellite ratio, indicating a lower orbital overlap between Ln 4f and ligand orbitals. Furthermore, analysis of the La(III) 3d region, demonstrates its unique sensitivity to chemical environment based on the covalency of the ligand environment. 

T00.00261: Exploration of new intermetallic compounds grown via pblock fluxes Julio Sarmiento The metal flux method has emerged as a strong tool for the synthesis of single crystals for a large number of intermetallic compounds. Intermetallic compounds are at the heart of exploratory growth and discovery of new materials due to their wide variety of physical properties, such as, e.g., superconductivity, topology, magnetism, thermoelectricity, etc. We have explored intermetallics with pblock elements as fluxes. Here we report on the growth, structures, and characterization of new compounds. While many binaries have been obtained, such as SmIn_{2}, InMn_{3}, SmTe_{2}, etc., these experiments open the door to continue the exploration to find new materials. For example, the intermetallic compound Cu_{2}SmSi_{2} was obtained using the flux technique with Indium as a passive flux. 

T00.00262: Geometric Control of Domain Structure Stability in Ferroelectric Nanotubes Aiden Ross The field of nanoscale ferroelectrics has utilized geometric confinement in thin films, nanodots, nanoislands, and strained superlattices to stabilize flux closures, vortices, skyrmions, and other topologically nontrivial polar states. Ferroelectric nanotubes provide a unique geometry with a large surfacetovolume ratio and vertical to lateral aspect ratio, and from these unique geometric properties, new polarization domain structures can be stabilized with unique fluxclosure topologies. Using phasefield modeling, we simulated the equilibrium polarization domain structure in PbZr0.52Ti0.48O3 nanotubes under different height and wall thickness conditions, and three unique domain structures were found. Each domain structure comprises an array of periodic fluxclosures and antifluxclosures pairs formed to minimize elastic and electrostatic energy. These domain structures differ by the frequency of the fluxclosure/antifluxclosure pairs along the perimeter and height. We demonstrate that the thermodynamic stability of these domain structures can be tuned by changing the nanotube geometry with wall thickness and height. 

T00.00263: CVDgrown amorphous SiC_{x}O_{y}Si heterojunction: A unique Schottky diode Sudipta Khamrui, Jonaki Mukherjee, Aprajita Sinha, Debamalya Banerjee Silicon oxycarbide (SiC_{x}O_{y}), commonly used as lowκ inter layer dielectric in technological 

T00.00264: Abinitio Calculations of Electronic Properties of Bulk and 2D Molybdenum Disulfide (MoS_{2}) Yuriy Malozovsky, GuangLin Zhao, Diola Bagayoko We present results from abinitio, selfconsistent density functional theory (DFT) calculations of electronic properties of molybdenum disulfide (MoS_{2}), for the bulk and a 2D sample. The bulk MoS_{2} (2HMoS_{2}) is in the hexagonal structure with the space group P6_{3}/mmc and Pearson symbol hP6 (#194); the 2D sample is also in the hexagonal structure with the space group P3m1. We utilized a local density approximation (LDA) potential and the linear combination of atomic orbital (LCAO) formalism. Our calculations performed a generalized minimization of the energy to reach the ground state, as required by the second DFT theorem. This process ensures the full, physical content of our findings that include electronic energy bands, total and partial densities of states, and electron and hole effective masses. Our calculated band gap for room temperature lattice constants of a= 3.16 Å and c=12.294 Å is 1.42 eV, for the bulk, and is indirect; it is 2.65 eV for the 2D samples, for lattice constants of a= 3.187 Å and c=31.87 Å, and is a direct band gap. 

T00.00265: Entanglement features on the dynamics of quantum polariton vortex. Juan Pablo Restrepo Cuartas, Herbert VinckPosada Indivisible excitations of a quantum system are the fundamental bricks of physical behaviour. In essential respects, they allow interpreting chance as the fundamental feature of quantum realism. This is the framework in which quantized vortices must be tackled, which are usually studied between a meanfield or coherent approach. Hence, we use an approach to analyse, in a general way, a quantized vortex under quantum coupling, i.e., indivisible excitation exchange. This fully quantized picture enables the system to undergo richer dynamics; the vortex core and its phase singularity follow a far from a plain family of trajectories. In this approach, the state operator's superposition principle allows light and matter entanglement. 

T00.00266: SelfOrganization of Organic Molecules on Surfaces Jacob Martin, Jessica E Bickel Organic semiconductors have advantages over their inorganic counterparts due to their ecofriendliness, cheap producibility, and applications in flexible electronics. However, organic semiconductors tend to have a lower conductivity than their inorganic counterparts. One possible method to increase the conductivity of organic semiconductors is selfassembly driven by a surface reconstruction that is a repeating topography across the surface of a substrate. This work examines pentacene, an organic semiconductor, on a very simple surface of graphite or graphene both experimentally and computationally. Experimentally we see limited evidence of a lowest energy orientation for pentacene that is thermally evaporated onto highly ordered pyrolytic graphite (HOPG). This is in agreement with computational DFT calculations that show, despite an AB stacking structure being the lowest energy orientation, this is a very shallow minima. Several orientations of pentacene, shifted laterally across the surface and rotated at each position, have a similar final energy. 

T00.00267: Different shapes of spin textures as a journey through the Brillouin zone Carlos Mera Acosta, Linding Yuan, Gustavo M Dalpian, Alex Zunger Crystallographic point group symmetry (CPGS) have long been known to classify compounds that have spinorbitinduced spin splitting. While taking a journey through the Brillouin zone (BZ) from one kpoint to another for a fixed CPGS, it is expected that the wave vector point group symmetry (WPGS) can change, and consequently, a qualitative change in the spin polarization pattern (SPP) can occur. However, the nature of the SPP change is generally unsuspected. We determine a full classification of the linearink SP patterns based on the polarity and chirality reflected in the WPGS. Specifically, the SP is bound to be parallel to the rotation axis and perpendicular to the mirror planes, and hence, symmetry operation types in WPGSs impose symmetry restriction to the SPP. For instance, the SPP is always parallel to the wave vector k in nonpolar chiral WPGSs since they contain only rotational symmetries. Examples of actual compounds with such prototypical spin textures verified by first principles DFT are given (Physical Review B 104, 104408 (2021)) and await experimental spinARPRES testing. Additionally, we use the determined relation between WPGS and SPP as a design principle to select compounds with multiple SPPs at different k valleys. Based on highthroughput calculations for 1481 compounds, we find 37 previously fabricated materials with multiple SPPs. 

T00.00268: Voltagecontrolled brightness of localized emitter arrays in monolayer WSe_{2} Zhuofa Chen, Weijun Luo, Edward McGee, Xi Ling, Anna K Swan Transitionmetal dichalcogenides (TMDC) monolayers are promising systems for optoelectronic devices due to their strong photoluminescence (PL), direct band gaps, large exciton binding energies, and favorable mechanical property for strain engineering. Herein, we report the electrostatic control of localized strain, and large exciton binding energy compared to RT. In this work, we demonstrate localized exciton emitter arrays in monolayer WSe_{2 }drytransferred. We demonstrate localized bright WSe_{2} emitter arrays on SiO_{2} nanopillars. The nanopillars generate, where a localized biaxial strain up to 0.6 % on WSe_{2}. The resulting electronic band structure changes funnelis introduced to WSe_{2}. We observe charge and exciton funneling to the pillar strain apex. A surprising, resulting in a significant enhancement in PL emission is either due to increased radiative or decreased nonradiative rates. We explore the mechanisms of PLexcitonic emission intensity variation by studying its. We find evidence the strainrelated confinement potential promotes the radiative and nonradiative decayprocess. We deploy electrostatic doping to further promote the excitonic emission intensities. We attribute the enhancement to the suppression of trion emission and nonradiative channels, including charge control to investigate the trion decay channel and power dependence study to like excitonexciton annihilation, and density dependence possibly causing enhanced PL via exciton to electronhole pair transition from screening.. Our work is importantpaves the way for strainengineered optoelectronics and has asheds insight on the potential application in large scale lightemitting devices using 2D materials. 

T00.00269: Protecting spin polarization in layered metal halide perovskites through dynamic polaron formation Franco V Camargo, Soumen Ghosh, Sean A Bourelle, Timo Neumann, Tim W van der Goor, Ravichandran Shivanna, Thomas Winkler, Giulio Cerullo, Felix Deschler Metal halide perovskites attracted intense research interest as promising materials for photovoltaic and spintronic applications. Due to the polar nature of their soft crystal lattice and quantumwelllike structures, they exhibit strong coupling between exciton and phonon modes. We investigated the impact of excitonphonon coupling on the spin dynamics of BA_{2}FAPbI_{7} (BA, Butylammonium; FA, Formamidinium) using femtosecond Faraday rotation and transient absorption spectroscopy. We observe that by coherently exciting far above the exciton resonance, the spin lifetime at 77K is increased by more than two orders of magnitude. Transient absorption measurements recover coherent phonon modes which are strongly coupled to excitons and enable the formation of a polaron state. The ultrafast formation of the polaron reduces the electronhole exchange which, in turn, slows down the rate of spin precession and protects spin polarization. Our results demonstrate that strong excitonphonon coupling in layered perovskites leads to a novel regime of excitonpolaron spin dynamics which can be optically selected. The ability to encode photoexcitation energy into spin lifetimes could be a promising strategy for future spintronicsphotonics applications. 

T00.00270: Chemical vapor transport growth and crystal structure of PbSb sulfosalts masoud mardani, shivani sharma, Kaya Wei, Theo Siegrist Zinkenite (ideally Pb_{9}Sb_{22}S_{42}) and Boulangerite (ideally Pb_{5}Sb_{4}S_{11}) are two Naturally occurring minerals that are predominantly ternary compounds of PbSbS with some impurities. We recently synthesized single crystals of these materials in the laboratory by chemical vapor transport (CVT) in a vacuumsealed quartz tube. Both samples were grown in an acicular shape where the zinkenite needles formed a textile shape similar to wool. Single crystal Xray diffraction measurement have been performed to explore the crystal structure at room temperature. The Rietveld refinement of singlecrystal XRD data has been performed that confirms that the Zinkenite crystallizes within hexagonal symmetry with lattice parameters a = 22.0965(4) Å and c = 4.31990(10) Å whereas the Boulangerite sample crystallizes within monoclinic symmetry with lattice parameters a = 8.04786(13) Å, b = 23.4732(4) Å, c = 21.5621(5) Å, and β = 100.7410(19) degrees. Further, the energydispersive Xray spectroscopy (EDS) shows that the stoichiometry of Zinkenite sample is roughly Pb_{12}Sb_{32}S_{54}. Physical properties of these samples will be reported. 

T00.00271: UVVIS spectroscopy study of room temperature spin state switching in a Fe(II) spin crossover molecular thin film Saeed Yazdani, Kourtney Collier, Grace Yang, Ashley Dale, Jared Phillips, Jian Zhang, Peter A Dowben, Ruihua Cheng For many spin crossover (SCO) complexes, transition from high spin to low spin occurs at a very low temperature. To implement this molecular system for device applications, it is crucial to tune the transition near room temperature. A ferroelectric layer with the capability of changing the electric polarization direction in the presence of an external electric field facilitates the switching of spin states in SCO molecules at room temperature. For this purpose, a polyvinylidine fluoridehexafluoropropylene (PVDFHFP) thin film prepared in the beta phase is crucial. In our study, a series of bilayer samples of [Fe{H_{2}B(pz)_{2}}_{2}(bipy)] (pz = tris(pyrazol11y)borohydride, bipy = 2,2’bipyridine) thin films on ferroelectric PVDFHFP substrates were fabricated. PVDFHFP thin films annealed at different temperatures were studied using Fouriertransform infrared spectroscopy (FTIR) and bilayer samples with different PVDFHFP thin film thicknesses were studied by UVVis spectroscopy. FTIR data indicates that PVDFHFP is dominated in the beta phase and UVVis spectroscopy reveals that room temperature switching of spin states in those molecules shows a strong dependence on the thickness of the ferroelectric substrate. 

T00.00272: Simulating realtime electron dynamics in hBN by solving semiconductor Bloch differential equations Mikhail Mallakhov, Antonio Picón, Giovanni Cistaro Resolving the realtime motion of electrons in complex systems is a key to enhancing the functionality and understanding the underlying mechanism of modern materials. Modern development in laser techniques of attosecond timescale gives us a tool to probe electron motion in a realtime resolution. However numerical simulation of the pumpprobe spectroscopy experiments is a challenging task. Solutions of BetheSalpeter equations [1,2] can give us the excitonic spectrum of the system, yet cannot give us timeresolved electron response to a laser beam. In our work, we propose to use the corestateresolved Bloch equations (cBE) formalism [3,4], a set of differential equations derived from the microscopic model of the system written in the representation of second quantization. The nonequilibrium population of different bands can be extracted then from the timedependent elements of the density matrix. Here we will show our calculations in which we are able to resolve the electron dynamics in hexagonal Boron Nitride (hBN) in a attosecond timescale. [1] Henriques et al, J. Phys.: Cond. Mat. 32 025304 (2020) [2] Rukelj et al, New J. Phys. 22 063052 (2020) [3] Picón et al, J. Phys. 21 043029 (2019) [4] Cistaro et al, Phys. Rev. Research 3 013144 (2021) 

T00.00273: Manipulation of the twodimensional hydrogenic defect states in monolayer MoS_{2} Bumsub Song, Young Hee Lee, Seok Joon Yun, Young Jae Song Indepth understanding of the charged object in atomicscale is crucial for both fundamental science and unprecedented functional applications such as ultrasmall memory devices. Here, we demonstrate a reversible switching of hydrogenic states of charged defects in MoS_{2} monolayer employing scanning tunneling microscopy and spectroscopy (STM/S). Bistable charge states of the defects are identified: negatively charged (1) and neutral (0), where they can be switched reversibly via STM tip manipulation. The negative charge state is characterized by the presence of the upward band bending and resulting depletion region in vicinity of the defects. The Coulomb potential of the negative charged perturbation is renormalized via dielectric screening of the host twodimensional semiconducting MoS2, which admits additional localized states near the valence band side. Thus, by controlling the defect charge, we “switch on” or “off” the ingap states. We show that the observed ingap states are the physical manifestation of the twodimensional Rydberg states. 

T00.00274: Effects of Ga doping on the phase transitions of V_{2}O_{3} Pavitra N Shanbhag V_{2}O_{3} undergoes a firstorder metalinsulator transition accompanied by magnetostructural transition (T_{MI}~160 K). Here, we report a comprehensive study on a gallium doped (4%) polycrystalline V_{2}O_{3} by employing a variety of experimental techniques such as synchrotron Xray diffraction, time of flight neutron diffraction, electrical transport, DC magnetization, heat capacity, thermal expansion, and Raman spectroscopy. Remarkably, the gallium doping in V_{2}O_{3} enhances the Neel temperature by 25 K (T_{N} = 185 K). Further, we find the decoupling of structural transition from the magnetic transition and a second order insulator  insulator transition (T_{II }~ 185 K) occurs without a sudden jump. Raman spectroscopic studies reveal the softening of E_{g }mode and the splitting of A_{1g} mode, due to lifting of degeneracy, in the rhombohedral phase (R3c) occur at slightly above T_{N}/T_{II }(T* = 195 K)_{. }Besides, the rhombohedral and monoclinic phases coexist in a broad temperature range and a complete phase transformation to monoclinic phase occurs at 127 K. 

T00.00275: Magnetoelectric effect in the honeycomblattice antiferromagnet BaNi_{2}(PO_{4})_{2} SWARNAMAYEE MISHRA Magnetoelectric materials exhibit induction of magnetization by an electric field or polarization by a magnetic field, which is promising for various applications. Here, we report a comprehensive investigation of the structural, magnetic, and electrical properties in a quasitwodimensional planar antiferromagnet BaNi_{2}(PO_{4})_{2}, which crystallizes in the rhombohedral structure (space group R3) consisting of honeycomb layers of Ni^{2+} ions. Magnetic susceptibility and heat capacity data reveal a longrange antiferromagnetic ordering of Ni^{2+} ions at T_{N} = 24 K. Interestingly, an applied magnetic field induces a dielectric anomaly and an electric polarization at T_{N} with the polarization proportional to the applied magnetic fields, demonstrating the linear magnetoelectric effect in BaNi_{2}(PO_{4})_{2} with a coupling coefficient of 1.67 ps/m. It is interesting to note that the magnetic symmetry associated with the magnetoelectric effect is 1', which allows all tensor elements of the magnetoelectric susceptibility. 

T00.00276: Berry curvature induced spin currents in a 2D Rashba system Priyadarshini Kapri, Bashab Dey, Prof. Tarun Kanti Ghosh


T00.00277: Increasing Photovoltaic Conversion Efficiency in GaAs/Si Tandem Solar Cells through NanoBonding^{TM} and Surface Energy Engineering Nimith Gurijala, Pranav Penmatcha, Siddu Jandhyala, Ajay Taduri, Aashi R Gurijala, Amber A Chow, Shaurya Khanna, Michelle Bertram, Christian Cornejo, Timoteo Diaz, Wesley Peng, Thilina Balasooriya, Mohammed Sahal, Dr. Robert J Culbertson, Dr. Karen L Kavanaugh, Dr. Nicole Herbots The theoretical photovoltaic efficiency (PVCE) for GaAs/Si tandem solar cells is 44%, but high T> 400°C during heteroepitaxy and Direct Wafer reduce PVCE to 33%. 

T00.00278: ElATools: A tool for predicting and analyzing anisotropic elastic properties of 2D and 3D materials Shahram Yalameha, Zahra Nourbakhsh, Daryoosh Vashaee In the last two decades, owing to the observation of anomalous mechanical properties in some materials, much effort has been taken to discover and investigate materials with such features. The negative linear compressibility (NLC), negative Poisson’s ratio (NPR) or auxeticity, and highlyanisotropic elastic modulus are the most critical anomalous elastic properties that appear in some materials due to stressstrain. These characteristics are visible by analysis and visualization of elastic tensors. Here, we introduce ElATools, a code developed to analyze anisotropic elastic properties. ElATools enables facile analysis of the secondorder elastic stiffness tensor of twodimensional (2D) and threedimensional (3D) materials. It can efficiently identify anomalous mechanical properties in 2D and 3D materials, central to designing and developing highperformance nanoscale electromechanical devices. In addition, it enables the investigation of the behavior of the elastic wave velocities and their anisotropic properties by solving the Christoffel equation. This tool can generate data for Machine Learning to detect and predict mechanical and anisotropy properties. 

T00.00279: Optical constants of CaF_{2} at 300 K from 0.03 to 6.5 eV Jaden R Love, Nuwanjula S Samarasingha Arachchige, Carlos Armenta, Stefan Zollner, Hyun Jung Kim We describe the optical properties of CaF_{2}, an insulator with an ultrawide band gap of 12 eV and a large exciton binding energy of 1 eV. The range of transparency (125 meV10 eV) makes CaF_{2} a prime substrate for optical devices, e.g., tunable filters using phase change memory materials. The optical constants of CaF_{2} were studied in the 1960s. With modern ellipsometry equipment, we revisited the optical constants of CaF_{2} (100) and (111) substrates. CaF_{2} has a Ramanactive T_{2g} mode and an infraredactive T_{2u} mode, split into a TO doublet and a LO singlet. The T_{2u} mode can be seen with FTIR ellipsometry and described by a Lorentzian. The energies are TO=261 cm^{1} and LO=477 cm^{1}, with an amplitude A=4.1, a broadening of 4 cm^{1}, and a highfrequency dielectric constant of 1.98. A dip in the reststrahlen band is due to twophonon absorption described by an anharmonically broadened Lorentzian. In the visible and near UV, normal dispersion can be described by a pole located at 7.48 eV and a TaucLorentz oscillator at 20 eV. The imaginary part of the pseudodielectric function <ε_{2}> is negative above 3 eV, indicating a surface layer of 25 nm thickness with a larger refractive index than the bulk. We apply the CaF_{2} optical constants to find the thickness of a SiO_{2} layer on CaF_{2}. 

T00.00280: Optical Characterization of Mn doped ITO Nano films Masoud Kaveh, Scott T Bender, Daniel M Hirt, William T Riffe, Costel Constantin Determination of the band structure evolution of Indium Tin Oxide (ITO) with increasing Mn concentration is a key factor in understanding the origin of ferromagnetism in this sample. Thin films of ITO with various Mn concentrations are deposited on glass substrate with various thicknesses from a few tens of nanometer up to around a micrometer using a DC magnetron sputtering coating method. We then investigate these samples with room temperature photoluminescence (PL), ellipsometry, scanning electron microscopy (SEMEDX), and xray diffraction (XRD). Topography measured with SEMEDX of the thin films, show welldefined particles with similar elongated geometries with aspect ratio>3, which are on average 50 nm wide and ~150 nm long. The chemical composition measured with SEM EDX spectrum shows all the constituent elements are present in the Mn doped ITO films. Structural measurements performed with XRD shows a decrease in lattice constant as Mn concentration increases. The PL and fluorometry measurements of the Mn doped films reveal blue and bluegreen emission peaks. The peaks are tentatively attributed to the vacancies or surface defects in our films. The PL intensity decreases by increasing Mn concentration which is tentatively attributed to upward shift of the valence band. 

T00.00281: Plasmon damping rates in Coulomb coupled 2D layers in a heterostructure. Dipendra Dahal, Godfrey A Gumbs, Andrii Iurov Coulomb excitations due to charge density oscillation are calculated for a double layer 

T00.00282: Optical and xray characterization of GeSn alloys on GaAs Haley B Woolf, Carola Emminger, Carlos Armenta, Stefan Zollner, Matt Kim In this poster, we describe the optical and xray characterization of a thick Ge_{1y}Sn_{y} alloy grown on GaAs by chemical vapor deposition. From (224) xray reciprocal space maps we find that the alloy layer is grown pseudomorphically on the GaAs substrate. Thus, we can use (004) rocking curves and reciprocal space maps to determine the alloy composition based on Vegard’s Law. We find y=0.011. 

T00.00283: Microscope and Optical Characterization of Ag2GeS3 Nanowires Masoud Kaveh, Scott T Bender, Callista M Skaggs, Xiaoyan Tan As a polar thermoelectric material, Ag2GeS3 is a potential candidate for transforming heat into electricity. However, the fundamental mechanisms that govern the thermoelectric properties are not fully comprehended yet. We use Transmission Electron Microscopy and photoluminescence measurements to characterize this sample. 6 mm pallets of Ag2GeS3 samples are prepared using the conventional solidstate method with binary sulfides (Ag2S and GeS2) as starting materials. The sample is then vacuum sealed and heated up to 1000C^{0 }for 12 hours, and held at that temperature for 168 hours. Scanning electron micrographs show semiconical shape nanowires (NW) with a base of ~200 nm in diameter and a tip of ~50 nm. NWs are about 2 um long and are randomly oriented. Selected area electron diffraction measurements reveal a combination of both monocrystalline and a polycrystalline structure. Highangle annular darkfield imaging helped to map element concentration on different parts of the NWs. Room temperature Photoluminescence (PL) measurements show multiple peaks near UV, yellowgreen, red and near infrared. 

T00.00284: Finitetemperature plasmons in αT_{3} materials. Yonatan Abranyos, Andrii Iurov, Liubov Zhemchuzhna, Godfrey A Gumbs, Danhong Huang We calculated the polarization function and plasmon excitations for all types of αT3 materials at various temperatures. We derived a semianalytical expression for a wide range of temperatures (not extra low and extra high ones as it was done in all previous works graphene). Apart from the plasma frequencies, we calculated the damping rates for four different relative hopping parameters α and for various temperatures. We have also derived analytical expressions for the polarization function in the longwave limit, as well as in the static limit for an αT3 lattice. Our results significantly depend on α and, therefore, are very different from graphene. 

T00.00285: Monte Carlo Simulation of Carrier Transport Helen McDonough, Nicholas A Mecholsky The semiclassical Monte Carlo method for charge transport simulation is a powerful tool to bridge the gap between abstract models and materials. Close correspondence of this model to processes occurring in the motion of the particle makes this method both intuitive to understand and tailorable to a specific problem. Despite simplicity of understanding, this method allows for sophisticated models, allowing, for example, the simulation of analytical band structures, or the inclusion of complex scattering mechanisms. The complexity of the model may be tailored to examine specific problems such as the effect of band warping on transport properties. Such simulations allow for the calculation of transport properties such as the average electron energy, drift velocity, mobility, diffusion coefficient, conductivity, Seebeck coefficient and electronic thermal conductivity for various materials. In light of this, we have created a prototype of a Monte Carlo simulation of electron transport in Arsenic doped Silicon under the influence of an electric field using Mathematica. I will discuss the current and future stages of this project. 

T00.00286: Rare Earth Doped Lithium Tetraborate as a Scintillation Detector Lauren E Samson, Elena Echeverria, John McClory, Katherine Shene, Juan A Colón Santana, Yaroslav Burak, Volodymyr Adamiv, Ihor Teslyuk, Lu Wang, WaiNing Mei, Kyle A Nelson, Benjamin W Montag, Douglas S McGregor, Archit Dhingra, Peter A Dowben, James Petrosky, Carolina C Ilie Monitoring the movement and the radiation of radioactive materials has been an important problem to solve in modern society, especially in homeland security and nuclear facilities. Due to low interaction with matter and a lack of charge, neutrons are difficult to detect. Various materials in the past have been utilized, however finding a material with a large neutron capture section as well as one that is blind to gamma rays is difficult. In our research, we have focused on lithium tetraborate, Li_{2}B_{4}O_{7}, a transparent crystalline material with great capability for neutron capture due to the nuclear isotopes B^{10} and L^{6} , as well as its stability at a wide range of temperatures. Advantages and challenges of different dopant materials are also discussed. 

T00.00287: Temperature dependence of the direct band gap of InSb from 80 to 800 K Melissa Rivero, Carola Emminger, Stefan Zollner, Nuwanjula S Samarasingha Arachchige In this undergraduate student poster, we describe measurements of the dielectric function of bulk InSb near the direct band gap using Fouriertransform infrared (FTIR) spectroscopic ellipsometry from 80 to 800 K in an ultrahigh vacuum (UHV) cryostat with diamond windows. Indium antimonide (InSb) is the zinc blende compound semiconductor with the smallest direct band gap (_{ }E_{0} = 0.18 eV at room temperature) due to its heavy elements and the large resulting spinorbit splitting and Darwin shifts. It also has a low melting point of 800 K. Previously, the band gap of InSb has only been measured optically up to room temperature [1] and estimated from Hall effect measurements of the effective mass up to 470 K. Ellipsometry measurements of the direct gap of InSb have been described in [2]. Calculations indicate that InSb should undergo a topological phase transition from semiconductor to semimetal (and topological insulator) at 600 K. It is interesting to see in the data if this transition occurs below the melting point of InSb. 

T00.00288: Tuning Magnetic Properties of MnPSe_{3} via Cu Intercalation Mohamed E Nawwar, Sogol Lotfi, Vicky DoanNguyen There has been a growing interest in magnetic van der Waals (vdW) compounds owing to their twodimensional magnetic properties, making them particularly suited for the developing field of spintronics. One particular family of vdW compounds, transitionmetal phosphorous trichalcogenides (MPX3, M = Mn, Ni, Fe, Cu, Co, etc. X = S and Se), has shown great potential in the field of magnonics. We study the magnetic nature of MnPSe_{3} by doping Cu into the structure and analyzing its impact on the longrange magnetic order. Powders of Mn_{1x}Cu_{x}PSe_{3} have been synthesized using the hightemperature solidstate method. Phase purity was confirmed using synchrotron powder XRay Diffraction (XRD), Pair Distribution Function (PDF), and Neutron Powder Diffraction (NPD). From our NPD, PDF, and XRD analysis, we find that Cu is most favorably found to be intercalated in the vdW gap of MnPSe_{3}, inducing a longrange magnetic order transformation as observed in magnetic susceptibility. Herein, we report magnetic susceptibility, PDF, XRD, and NPD for Mn_{1x}Cu_{x}PSe_{3}. 

T00.00289: Add a Pinch of Tetrel: The Transformation of a Centrosymmetric Metal into a Nonsymmorphic and Chiral Semiconductor Shannon J Lee, Gayatri Viswanathan, Scott L Carnahan, Colin P Harmer, Georgiy Akopov, Aaron J Rossini, Gordon J Miller, Kirill Kovnir Centrosymmetric skutterudite RhP_{3} was converted to a nonsymmorphic and chiral compound RhSi_{0.3}P_{2.7} (space group P2_{1}2_{1}2_{1}) by means of partial replacement of Si for P. The structure, determined by a combination of Xray crystallography and solid state ^{31}P NMR, exhibits branched polyanionic P/Si chains that are unique among metal phosphides. A driving force to stabilize the locally noncentrosymmetric cisRhSi_{2}P_{4} and facRhSi_{3}P_{3} fragments was πelectron backdonation between the Rh t_{2g}type orbitals and the unoccupied antibonding Si/P orbitals, which was more effective for Si than for P. In situ studies and total energy calculations revealed the metastable nature of RhSi_{0.3}P_{2.7}. Electronic structure calculations predicted RhP_{3} to be metallic which was confirmed by transport properties measurements. In contrast, the electronic structure for chiral RhSi_{0.3}P_{2.7} contained a bandgap, and this compound was shown to be a narrow gap semiconductor. 

T00.00290: Strong RashbaDresselhaus Effect in Nonchiral 2D RuddlesdenPopper Perovskites Tho Nguyen Chirality transfer from organic chiral molecules to lead halides has been theorized as the origin of the strong RashbaDresselhaus effect causing large circular dichroism (CD) and circularly polarized luminescence (CPL) in metal halide perovskites (MHPs). Here, we provide a concrete empirical evidence that such strong CD and CPL can occur even in nonchiral 2D RuddlesdenPopper perovskites (RPPs) such as in (BA)_{2}(MA)_{n1}Pb_{n}I_{3n+1} (where MA = CH_{3}NH_{3} and BA = CH_{3}(CH_{2})_{3}NH_{3}). The CD and CPL responses occuring at the excitonic transition of the MHPs are strongest (~100 mdeg and 4.8%, respectively) when a single lead halide octahedral [PbI_{6}]^{4} layer is repeatedly stacked between two nonchiral molecules BA^{+} (n = 1). However, they are rapidly quenched as n increases. We hypothesize that strong RashbaDresselhaus splitting in the 2D RPPs originates the strong CD and CPL signatures. Density functional theory (DFT) calculations reveal that the large interlayer distortions in the inorganic layers at the organic/inorganic interface gives raise to the strong RashbaDresselhaus splitting. A RashbaDresselhaus field of 600 mT and 50 mT for n = 1 and 2, respectively, are estimated by magnetic circular dichroism (MCD) spectroscopy. Our studies may have significant impact on designing 2D RPPs with large RashbaDresselhaus effects at room temperature for spintronic applications. 

T00.00291: Studying Elastic Constants of Potassium Lithium Tantalate using Ultrasonic Pulse Echo Probing Nathanael J Hillyer Ferroelectrics are characterized by spontaneous polarization appearing at critical temperature T_{c}. In some materials, called relaxors, polarization appears over a range of temperatures around T_{c}. Such materials are particularly interesting for numerous applications from capacitors and memory storage to actuators and nanopositioning. Many aspects of the relaxor ferroelectricity phenomenon are still unclear. One of the representatives of such materials is K_{1x}Li_{x}TaO_{3} (KLT). We report on the study of temperature dependences of c_{11} elastic constants in several KLT crystals with x = 0.01, 0.1, and 0.2 using ultrasound pulse echo technique in the temperature range of 65 – 300 K. By shooting an ultrasound pressure pulse and recording its echoes, we determine the speed of compressive wave, which is related to the c_{11} constant. The relaxor transition is marked by significant anomalous softening of the c_{11} in the neighborhood of T_{c}. 

T00.00292: Dielectric Properties of Nanostructured ZnO Using Impedance Spectroscopy Grant M Mayberry, Parameswar Harikumar Nanostructured ZnO has been investigated as an ntype semiconductor for thirdgeneration photovoltaics. In this study, we focus on the dielectric, and in turn the optical properties of 21.9 nm spherical ZnO nanoparticles at room temperature, in both powder form and suspension in a liquid. The dielectric properties determined from this method can then be used to model a nanomaterial's optical absorption properties in photovoltaics or other electronic devices. Impedance spectra in the frequency range of 100Hz5.1 MHz were used to investigate the frequencydependent dielectric properties of ZnO nanoparticles. ZnO particles used in this study were suspended in variable volume fractions up to ~1% in deionized (DI) water and unrefined organic coconut oil and sonicated for variable durations before and during the experiment. Small volumes of the resulting suspension were injected sequentially into a dielectric cell for measuring frequency response. Dry particle tests were also conducted similarly. Impedance data suggests that the dielectric behavior of ZnO in a host fluid is highly dependent on sonication before and during the test, is a much stronger dipole in more polar fluids, and has a perceived dielectric constant much larger in a suspension than as a dry particle. 

T00.00293: Metaldoped silicon diodes for radiation sensing applications Joseph O Bodunrin, Sabata J Moloi Crystalline silicon (Si) of different concentration types was doped with iron (Fe) and cadmium (Cd) metals. The doping was achieved by implantation of Si with metals at an energy of 160 keV. Different material characterization techniques were used to confirm the presence of the metals in Si prior to the fabrication of Schottky diodes. Schottky diodes fabricated on unimplanted and metalimplanted Si were characterized at room temperature using currentvoltage (IV) and capacitancevoltage (CV) techniques to investigate a change in electrical properties of the diodes due to metal doping. The diodes were then irradiated by 4 MeV protons and recharacterized to establish a change in diode properties due to irradiation. A change in different diode parameters due to metal doping and irradiation was also investigated. The results were explained in terms of the defects induced by metals in Si and are important for an ongoing quest to improve the efficiency of Si radiation detectors for current and future highenergy physics experiments and other applications. It was suggested for the first time, that Fe and Cd were suitable dopants in a study to improve the radiation hardness of Si through the defectengineering method in this work. 

T00.00294: Magnetic field dependence of the magnetoelectric effect of PZT/NFO multiferroic composite at the electromagnetic resonance Alexandre J Gualdi, Adilson Jesus A de Oliveira, Fabio L Zabotto, Ducinei Garcia Magnetoelectricity is related to the interaction between the magnetic and electric subsystems in a given material. The combination of piezoelectric and magnetostrictive materials gives rise to the magnetoelectric effect (ME) due to mechanical stress between the constituent phases. At electromechanical resonance (EMR) the ME may improve the ME by several orders. In particular, for the 22 composite BST8/NFO the ME is 300 times higher than any other frequencies. This work studied the ME of 30 PZT/NFO multiferroic composite at the EMR frequency. 

T00.00295: Lowtemperature heteroepitaxy of Ge_{1y}Sn_{y} binary alloy using chemical vapour deposition Pedram Jahandar Germanium tin (Ge_{1y}Sn_{y}) binary alloy is an intriguing group IV semiconducting material for various electronic and optoelectronic applications. Due to low solid solubility of Sn in Ge (0.6 at.%) and their large lattice mismatch (14.7 %), epitaxial growth of Ge_{1y}Sn_{y} alloys with Sn concentrations exceeding 0.6 at.% with low defects density has been a challenging task. Despite all challenges in the growth of Ge_{1y}Sn_{y}, researchers have succeeded in growing these epilayers using various techniques, however, chemical vapour deposition (CVD) is the most important growth technique in terms of applicability and practicability. As Ge_{1y}Sn_{y} physical and electrical properties sensitively depend on its Sn concentration and lattice strain, it is necessary to fully understand the effect of CVD growth conditions on these Ge_{1y}Sn_{y} epilayers. In this work, heteroepitaxy of Ge_{1y}Sn_{y} is achieved at a very low temperature (240 ℃) which has previously been reported to be an impossible task. Growing at such low temperature can provide a high quality fully strained Ge_{1y}Sn_{y} epilayer with high Sn concentration (over 13 at.%) which could be used to construct quantum wells and other complex structurs. 

T00.00296: Elastic properties of K_{1x}Li_{x}TaO_{3} (KLT) Ferroelectric Relaxor Crystals studied by Resonant Ultrasound Spectroscopy (RUS). Matthew P Yoder, Oleksiy Svitelskiy, Nathan Quattroci, Nathaneal Hillyer, Emily M Gima, Grace Yong, Lynn A Boatner Singlecrystalline KLT is a rather underinvestigated material. However, it represents a relatively simple model for relaxor ferroelectricity phenomenon; its optical transparency makes it a candidate for photonics applications. We report the results of our study of temperature dependences of elastic stiffness tensor parameters for a set of crystals with x = 0.01, 0.1, and 0.2 at temperatures ranging from room down to 80K. Anomalous softening of these parameters reveal the temperatures at which the phase transition occurs, socalled Curie temperatures T_{c}, where the unique properties of the material are most prominent. We found T_{c} to vary with the concentration of lithium. At x = 0.2, the T_{c} was estimated at 150K and at x = 0.1 the T_{c} was about 120K. At x = 0.01 the Tc fell below 80K, which requires further study. 

T00.00297: Ni_{3}Si_{2} Nanowires for Efficient Electron Field Emission and Limitations of the FowlerNordheim Model Emma Zeng, Amina B Belkadi, Abdel F Isakovic We report on topdown nanofabricated Ni_{3}Si_{2} nanowires and test of their electron field emission capabilities. The results include low turnon electric field, E_{ON}, moderate work function, Φ, and the field enhancement factor, β, the last parameter being customizable through nanofabrication. The growth and nanofabrication processes ensure a stable NitoSi stoichiometry, and we demonstrate highly repeatable J vs. E curves. We also report on the issues ahead in the field of nanowiresbased electron mission, as there are quantitative limitations of the applicability of the FowlerNordheim (FN) model, which will become increasingly apparent as we continue to optimize field emission of electrons. To this end, we suggest adding the studies of surfacetovolume ratio effects of the nanowires as another standard for comparison, in order to lead to the input form of the density of states as quantum effects becoming more prominent. This is relevant for increasingly quantum nature of electrons field emission, and calls for analysis of experiments without FN framework. 

T00.00298: Role of knockon in electron beam induced etching of diamond Marco Fronzi, Michael Ford, James Bishop, Milos Toth Electron beam induced etching (EBIE) has recently emerged as a promising directwrite nanofabrication technique. EBIE is typically assumed to proceed entirely through chemical pathways driven by electron electron interactions. Here we show that knockon (i.e., momentum transfer from electrons to nuclei) can play a significant role in EBIE, even at electron beam energies as low as 1.5 keV. Specifically, we calculate knockon crosssections for H, D, O and CO on the surface of diamond and show experimentally that they affect the kinetics of EBIE performed using oxygen, hydrogen and deuterium etch precursors. Our results advance basic understanding of electronadsorbate interactions, particularly in relation to EBIE and the related techniques of electron beaminduced deposition and surface functionalisation. 

T00.00299: Title: Negative Photoconductivity in Perovskite Semiconductors Light exposure usually cause an increase in photoconductivity in perovskite semiconductors. However, we will discuss lightinduced negative photoconductivity in perovskite semiconductors. Naveen K Tailor, Soumitra Satapathi Photodetection is one of the main applications in the optoelectronic devices and photodetectionbased devices are extensively used in our daily gadgets. All the commercialized photodetectors (such as Silicon (Si), Gallium Arsenide (GaAs), Indium Gallium Arsenide (InGaAs)) work on the principle of positive photoconductivity (PPC). However, an opposite phenomenon known as negative photoconductivity has been also detected in inorganic (dopedSi, PbTe, 2D materials), organic (Graphene, carbon nanotubes) and organicinorganic hybrid (halide perovskites) materials. A negative photoconductivity (NPC) occurs when a decrease in the conductivity takes place during illumination conditions.Here, we demonstatred lightinduced negative photoconductivity with slow recovery in lead free Cs_{3}Bi_{2}Cl_{9} and Cs_{3}Bi_{2}Br_{9 }perovskite single crystals. The femtosecond transient reflectance (fsTR) spectroscopy studies further reveal these electronic transport properties were due to the formation of lightactivated metastable trap states in Cs_{3}Bi_{2}Cl_{9 }crystal and formation of Vk center in Cs_{3}Bi_{2}Br_{9 }perovskite single crystals. The figure of merits of Cs_{3}Bi_{2}Cl_{9} singlecrystal detectors such as responsivity (17 mA/W), detectivity (6.23 × 10^{11} Jones) and the ratio of current in dark to light (~7160) was calculated. For Cs_{3}Bi_{2}Br_{9 }crystal, figure of merits estimated as responsivity (6.42 mA/W), detectivity (2.51 x 10" Jones), and current in a dark to light ratio (~20). This observation for these single crystals, which were optically active but showed retroactive photocurrent on irradiation, remained unique for such materials. This work demonstartes the application of NPC phenomenon can be used to fabricate the ultrasensitive detectors. 

T00.00300: GENERAL PHYSICS


T00.00301: Selfinduced vortex and antivortex states in dissipatively coupled laser arrays Mostafa Honari Latifpour, Jiajie Ding, Mirko Barbuto, So Takei, MohammadAli Miri The twodimensional classical XY model consists of a lattice of interacting spins that rotate in a plane. Recently, it has been realized that dissipative coupling in laser arrays allows for optical simulation of the classical XY model, where the phase of a laser plays the role of a classical spin degree of freedom, and the Lyapunov function governing such a dissipative system emulates the XY Hamiltonian. Here, we show that vortex and antivortex phase patterns can from spontaneously in laser arrays, in analogy with the topological defects of the XY model. The stability of such vortex/antivortex states depends critically on the relative lifetimes of the optical resonance and the fluorescence processes in the lasers. These results provide insight in investigating topological defects in laser systems, while it introduces a new approach for generating optical vortex beams without a need for external spatial phase modulation. 

T00.00302: Thermally Drawn Piezoelectric Fiber Enables Fabric for Acoustic Healthcare Monitoring Grace H Noel Thermally drawn piezoelectric fibers woven into clothing can continually monitor heartrate and breathing rate. In thermal drawing, viscoelastic materials flow in a laminar regime, maintaining the crosssectional geometry of the macroscopic preform. In the fiber device, the piezoelectric composite of P(VDFTrFE) and barium titanate (BTO) nanoparticles is flanked by carbonloaded polycarbonate electrodes and encapsulated in an elastomer cladding. The d_{31} piezoelectric coefficient is 46 pC/N, more than double previously reported values. Evidently, neither the thermal drawing nor the incorporation of BTO alone explains the enhanced d_{31}. During the draw, cavities form between the polymer and the particle on either side of the particle in the direction of the draw. It is hypothesized that the piezoelectric domain thus functions as a novel ferroelectret material. The sensitivity of the fiber woven into fabric is comparable to handheld microphones, and fibers reliably detect heartbeat and breathing. Arrays of fibers are used to determine the direction of a sound source with 1degree accuracy. In everyday clothing, fibers can continuously capture acoustic signals that provide the wearer with insight into their health, making healthcare more accessible outside clinical settings. 

T00.00303: Fast coherent control of a NitrogenVacancy spin ensemble in Diamond using a KTaO_{3 }dielectric resonator at cryogenic temperatures Hyma H Vallabhapurapu Microwave delivery to samples in a cryogenic environment can pose experimental challenges such as restricting optical access, space constraints and heat generation. Moreover, existing solutions that overcome various experimental restrictions do not necessarily provide a large, homogeneous oscillating magnetic field over macroscopic lengthscales, which is required for control of spin ensembles or fast gate operations in scaledup quantum computing implementations. Here we show [1] fast and coherent control of a negatively charged nitrogen vacancy spin ensemble by taking advantage of the high permittivity of a KTaO_{3} dielectric resonator at cryogenic temperatures. We achieve Rabi frequencies of up to 48 MHz, with a total fieldtopower conversion factor CP = 9.7 mT/√?? (191 MHzRabi/√??). We use the nitrogen vacancy center spin ensemble to probe the quality factor, the coherent enhancement, and the spatial distribution of the magnetic field inside the diamond sample. The key advantages of the dielectric resonator utilized in this work are: ease of assembly, insitu tuneability, a high magnetic field conversion efficiency, a low volume footprint, and optical transparency. This makes KTaO_{3} dielectric resonators a promising platform for the delivery of microwave fields for the control of spins in various materials at cryogenic temperatures. 

T00.00304: Generation of midinfrared femtosecond pulses tunable in the 310 μm range from an optical parametric amplifier Andrea Villa, Aaron M Ross, Riccardo Gotti, Marco Lamperti, Francesco Scotognella, Giulio Cerullo, Marco Marangoni In this work we present an optical parametric amplifier (OPA), pumped by an amplified femtosecond Yb:KGW laser and directly generating midinfrared (MIR) pulses in a broad tuning range, thus allowing to cover the entire vibrational spectrum between 2.5 and 10 μm. Avoiding the usual differencefrequency generation (DFG) stage to access the MIR region simplifies the setup while enabling high conversion efficiencies. The twostage design employs a beta barium borate (BBO) crystal for the first stage, which is pumped at 0.515 μm and amplifies a nearinfrared (NIR) seed in the 1.11.7 μm. Instead, the second stage exploits either periodically poled lithium niobate (PPLN), which is optimal for the CH/OH bonds stretching region (35 μm), or LiGaS_{2} (LGS), which allows the extension of the tunability range to the fingerprint region (up to 10 μm). The system has been characterized by measuring the spectra of the pulses, the signal and idler output powers, the second stage gain and by calculating the transform limited durations. We anticipate applications of this source to ultrafast vibrational spectroscopy, Fouriertransform IR microscopy and photothermal IR microscopy. 

T00.00305: Simulations of Xray Sources from Xray Tubes to vanderWaals Materials Dustin Enyeart I plan to present simulations of several xray sources. These sources include an xray tube, an undulator and free electrons in vanderWaals materials. The xray tube and undulator are simulated in Geant4. The trajectories of the free electrons in the vanderWaals materials are simulated by first calculating the electron density in the vanderWaals materials using density functional theory. 

T00.00306: Demonstration of a threedimensional current mapping technique around a superconductor in a prototype of a conventional superconducting fault current limiter Md A Ali, Satyajit S Banerjee A Superconducting Fault Current Limiter (SCFCL) is a device that limits large current surges in a power distribution network. Despite its advantages, conventional SCFCL has no mechanism to inhibit the generation of instabilities like hot spots in the superconductor. Such instabilities often damage the superconductor, failing the SCFCL during its operation. Here, we describe the threedimensional current mapping technique around the superconductor of a prototype superconducting fault current limiter. The SCFCL has an array of Hall sensors distributed around the superconductor inside the SCFCL. Signals from the Hall sensor array are used to generate in realtime threedimensional maps of local average current distribution at different locations around the superconductor. Our measurement at currents less than the critical current shows a nonuniform current distribution around the superconductor. This is a signature of nonuniform flux pinning across the superconductor. The capability of realtime monitoring and mapping of average local current distribution offers a unique way to detect instabilities around the superconductor in the SCFCL. We propose a design that provides early detection and protection against instabilities developing in the superconductor and offers an added flexibility, namely, allowing for a usersettable fault current threshold. This ability allows fault limiting operation to begin at the initial stages of the fault development. Such flexibility is not offered in conventional SCFCL. Using the above, we also show inherent limitations in the earlier design of metallic shunts placed in direct contact with superconductors. 

T00.00307: Temperature tunable Studies of thermochromic VO_{2} and WVO_{2} hybridizised with Flexible IR  1D Photonic crystals for energy efficent smart windows Dipti Umed Singh The effect of flexible Infrared 1D photonic crystal as a spectral selective tunable device with Vanadium dioxide as a phase changing material for smart windows application is being studied. Vanadium Dioxide goes under semiconducting to IR  blocking metallic Phase transition around 68º C due to change in its crystal structure from monoclinic to rutile. Monoclinic VO_{2} nanostructures with tuned crystallinity due to ambient change is studied. VO_{2} thin films were incorporated with 40 % transmitting DBR. Influence of DBR stacking is also being studied, and by slight increase in no. of stacks, nearly 100% reflecting DBR is fabricated, the optical transmission of metallic VO_{2} films on DBR with increase in temperature nearly vanishes in the nearIR spectrum and make it a perfect Photo absorber in IR region. To make these energy efficient smart window design more practical, the transition temperature of VO_{2} is reduced to near room temperature by doping with tungsten, which is the most suitable dopant for temperature reduction. 1.1 at. % W  Doped VO_{2} were synthesized to brought the temperature of IMT transition to 37 ºC from 68 ºC. WVO_{2} nanostructures were incorporated with Infrared Flexible 1D photonic crystal and optical transmission vanishes completely with corresponding reflection decrease, this made these structure as spectral selective tunable device which can efficiently control the optical modulation of WVO_{2 }nanostructure with change in temperature. WVO_{2}/DBR hybrid structure can substantially control the heat flux and also offers retrofitting application for energy economy. 

T00.00308: Abstract Withdrawn


T00.00309: GaAs/Si hybrid mode photonic crystal nanobeam cavity for saturable nonlinearity Mohammad Habibur Rahaman, Mustafa Atabey Buyukkaya, Yuqi Zhao, ChangMin Lee, Edo Waks Silicon photonics is an excellent platform for high yields and seamless onchip integration with electronics, lowpower consumption, and lowcost manufacturing. However, silicon has a small nonlinear optic coefficient, and it is challenging to realize nonlinear optical response, which is essential for versatile phenomena that linear systems cannot provide. As an alternative, IIIV semiconductor offers significant nonlinear behavior based on quantum well or quantum dot structures. Hybrid integration of IIIV semiconductor into silicon photonic circuit ensures to combine those two functionalities. Still, designing a cavity incorporating hybridmode in both Si and GaAs has not been done. This work presents a GaAs/silicon photonic crystal cavity with a gallium arsenide plate on top of a silicon cavity based on hybridmode using 3D FDTD simulation at telecom wavelength. Onresonance nonlinear transmission based on saturable absorption is obtained by embedding InAs quantum dots in the GaAs region. Our hybridmode cavity is easy to fabricate without precise Si/GaAs alignment, and it has low threshold power under continuous wave (CW) operation and high onresonance transmission. 

T00.00310: LightInitiated Reactive Processing in FFF 3D Printed HighPerformance Polymers Austin W Riggins, Nadim S Hmeidat, Jian H Yu, Mark D Dadmun Fused filament fabrication (FFF) is the most popular 3D printing technique; however, FFF structures are inherently anisotropic. Factors such as the high molecular weight of the feedstock polymer and the complex thermal and shear history of the print process inhibits diffusion of polymer chains between printed layers. This leads to weak interfilament adhesion, which compromises mechanical properties perpendicular to the raster direction. In a previous study by our research group, lowmolecular weight additives (LMWA) functionalized with UV reactive moieties were incorporated into a polylactic acid feedstock. During the printing process, these additives surface segregated to the layer interfaces; then, upon irradiation with UV light, crosslinks were formed across the interfaces and nearly isotropic structures were achieved. We have now begun to transition such reactive processing schemes into FFF prints with two highperformance polymers: poly(ether ether ketone) (PEEK) and poly(ether imide) (PEI). This presentation will describe our investigations into the effects of UV/visible light on the mechanical properties of our PEEK and PEI printed structures, again incorporating LMWAs to promote polymer chain diffusivity and small molecule photoinitiators to facilitate reactivity. 

T00.00311: A Thermionic Cathode with Functionalized Carbon Nanotubes as Emitters Feng Jin, Ansibert Miruko, Ethan Carman A thermionic cathode based on barium strontium oxide coated CNTs is presented. The cathode resembles a conventional oxide cathode structurally. It has a coiled tungsten filament as base structure, but uses barium oxide coated CNTs as emitters instead of the widely used barium strontium calcium oxide powder mixture in conventional oxide cathodes. Plasma enhanced chemical vapor deposition was used to grow CNTs onto the coiled tungsten filament; and magnetron sputtering was used to deposit the barium strontium oxide coating onto the CNT surface; both are highly versatile and adaptable techniques. With the combination of a low work function surface and a large field effect induced by the CNTs, the oxide coated CNT emitters help produce a strong thermionic emission from the cathode. The thermionic emission current density of 2.9 A/cm^{2} was obtained at 1395 K and 2.5 V/mm, which is three times of that from a conventional oxide cathode. The cathode was also tested in low pressure argon gas discharge to assess its adaptability and performance in a real plasma environment. The cathode fall of the cathode was found to be much lower than that of a conventional oxide cathode, indicating that it is highly efficient in emitting electrons. 

T00.00312: Separation of Microparticles using Optical Whispering Gallery Mode (WGM) Resonances Rona J Ganthier Phenomenon of WGM resonances has been known for millennia from acoustics; domes of many cathedrals are famous for it, where silent sound can travel multiple times around the circumference. In optical WGM resonators (e.g. microspheres) light in resonance may travel around the resonator for more than a million of times. One of the properties of such a resonance is giant amplification of the light propelling forces that can move microparticles 5 to 50 microns in diameter microparticles by distances up to 0.20.4 mm. We report on the progress in our attempt to harness this phenomenon for selecting and separating microparticles. Our goal is to develop an optical microfluidic cell, where evanescent light from the tapered down to 1 micron in diameter optical fiber would capture and transport to a separate chamber suspended in water microspheres whose WGM resonance is matching the light wavelength. Such method may find applications in photonics, biomechanics, and medicine. 

T00.00313: Fiber Optic Interferometry for Nanomechanical Displacement Detection Anna Rathbun, Craig Story, Oleksiy Svitelskiy Nanoelectromechanical (NEMS) resonators with their small masses, high frequencies, and low energy dissipation, show potential for sensitive and precise applications in detecting mass, force, and other physical quantities. Optical interferometry is an important tool for NEMS. Most NEMS instruments utilize costly and hard to tune freespace design, whereas fiber optic methods have potential to be more stable, compact, and cost effective. We present an interferometer based on a fiberoptic circulator and a 635 nm laser. Having passed through the fiber, light is reflected back from the NEMS surface and from the tip of the fiber. The circulator directs reflected light to the detector, where the interference from the combination of the reflected beams occurs. Excited using an ultrasound transducer, NEMS oscillations cause oscillations of the interference signal that are recorded, for example, with a spectrum analyzer. Results of testing the interferometer are presented. Authors are thankful to Atakan B. Ari and M. Selim Hanay for providing our sample, and to Kamil Ekinci for continuous help. 

T00.00314: INDUSTRIAL AND APPLIED PHYSICS


T00.00315: Visualization of spatially confined air plasma in macro (mm) tubes NAGARAJU GUTHIKONDA, D.P.S.L. Kameswari, S. Sai Shiva, E. Manikanta, S. Sree Harsha, V.R. Ikkurthi, P. Prem Kiran The spatially confined nanosecond pulse laser induced air plasma generated in a rectangular glass tube is visualized through shadowgraphy and selfemission, to understand the role of the radial shock wave compression and reheating of air plasma. Second harmonic Nd: YAG laser pulses with 10 ns pulse width, peak intensities in the range of 2.5  20 ×10^{9} W/cm^{2 }corresponding to the laser energies of 50400 mJ were used to create air plasma at the center of the rectangular tube of dimension 12 mm (L) x 8 mm (D). The shadowgraphy visualization showed that, the strength of the reflected radial shock wave depends on the input laser energy, and cavity aspect ratio (L/D). These parameters were observed to play a crucial role in the enhancement of the plasma properties. Similarly, the selfemission imaging revealed that, due to the compression of radial shock waves, the plasma source split into localized multiple emission centers, that are recombine together and form as a single source at longer time scales. The confined air plasma and shock wave evolution are compared with that of free expansion for different input laser energies. The comparison shows that, the plasma properties and its lifetime are enhanced by 1.52 times with the spatial confinement. 

T00.00316: Sound velocity measurements on metals and Earthforming materials at high pressure and temperature Sibo Chen, Xintong Qi, Siheng Wang, Man Xu, Tony Yu, Yanbin Wang, Baosheng Li Laboratorybased sound velocity measurements at high pressure and temperature are essential to the understanding of the elastic response of materials at extreme conditions. In this study, we introduce our simultaneous equation of state and sound velocity measurements on metals (W) and Earthforming minerals (lawsonite). We use a Kawaitype (T25) large volume multianvil apparatus installed at beamline 13IDD of GSECARS/APS to generate high pressures. The apparatus compresses eight WC cubes, each with a corner truncated to a prespecified edge length, forming an octahedral cavity, within which a MgOMgAl_{2}O_{4} octahedral pressure transmitting medium was compressed. The sample was located within a graphite sleeve heater inside the octahedron, with a buffer rod to connect the sample to one of the WC cubic anvils, to which a piezoelectric acoustic transducer was attached to generate and receive acoustic signals. Roundtrip acoustic travel times through the sample were measured using the pulseecho overlap method of ultrasonic interferometry. By using a dualmode piezoelectric transducer (resonance frequency of 50 MHz and 30 MHz for P and S waves, respectively), P and S wave travel times were obtained simultaneously with an accuracy of ~0.1%. In the experiments conducted in conjunction with synchrotron Xray radiation, the sample length was determined from Xray radiographic imaging whereas the unit cell volumes (hence density) of the sample were obtained by energydispersive Xray diffraction. By fitting the sound velocity and density data to the 3^{rd}order finite strain equations, we determined the bulk and shear moduli as well as their respective pressure and temperature derivatives. At this meeting, new results for tungsten and lawsonite up to 10.5 GPa and 1073 K will be presented. 

T00.00317: 16BMD –A Versatile Static Compression Beamline at HPCAT Changyong Park, Dmitry Popov, Guoyin Shen, Curtis KenneyBenson, Eric Rod, Arun Bommannavar, Maddury S Somayazulu HPCAT 16BMD beamline is dedicated for static compression studies using a variety of synchrotron xray techniques including microXRD, XAS, and microtomography imaging. The beamline utilizes a fixedexit geometry of the monochromatic beam with covered energy range of 660 keV and a robust energy scanning capability with high fidelity energy calibration. Recently, the monochromator has been upgraded with a dualmode double crystal monochromator (DCM) and double multilayer monochromator (DMM) combined in a single chamber. The DCM consists of Si 111 single crystals in a pseudo channelcut geometry, providing ΔE/E = 1.45×10^{4} energy resolution for Xray absorption spectroscopy and microXRD. The DMM is made of 400 layers of NiB_{4}C bilayer with 30 Å dspacing, providing ~1.3% bandwidth pink beam with ~6090 times DCM intensities that benefits fast scanning Xray diffraction imaging and parallel beam tomographic imaging. With the new choices of incident beam, a variety of static compression experiments can be conducted combined with resistive heating and cryocooling sample environments. A detailed specification of the dualmode monochromator and some selected case studies are presented. 

T00.00318: Three Dimensional Laser Induced Blowoff Simulation Studies from 20 µm Thick Aluminum Foil Sai Shiva S, Nagaraju Guthikonda, Sree Harsha S, Venkata Ramana Ikkurthi, Prem Kiran P Nanosecond laser induced material blowoff from the rear side of 20 µm thick aluminum foil confined with a glass substrate is performed using the threedimensional (3D) and three temperature FLASH radiation hydrodynamic code. The material blowoff is induced by irradiating 10 ns, 532 nm, and 25  200 mJ (2 – 10 GW/cm^{2}) laser energy pulses at the glassfoil interface. Due to the spatial confinement of the foil, high pressure, specific energy, and temperature buildup at the interface resulting in the material blowoff from the rear side of the foil, along the laser propagation direction. The hydrodynamics of the blowoff material in the form of plasma and shock wave expanding in ambient air is affected by the input laser conditions and the substrate used. In this work, we present the threedimensional analysis of the hydrodynamics of laser induced blowoff (LIBO) plasma and shock waves expanding in ambient atmospheric air. The simulations were performed for different input laser energies to understand the effect of energy on LIBO parameters such as shock velocity, plasma pressure, temperature, and energy. The simulated blowoff shock expansion is correlated with the experimental results to understand the underlying physics of the blowoff process. 

T00.00319: Structures and Transport Properties of Hydrogenated TiZr Alloys under High Pressure Bin Li, Soonbeom Seo, Dongzhou Zhang, Tuson Park, Jaeyong Kim Effects of pressure on the structure, electronic resistance, and the critical magnetic field for hydrogenated TiZr alloys were investigated to study the transport properties of hydrogenabsorbing materials under compression. With increasing pressure from ambient to 50 GPa, results of synchrotronbased Xray diffraction measurement revealed that the structure of the pure TiZr alloys prepared at equiatomic composition changed from an hcp to a bcc phase through an hcpomega phase, while hydrogenated ones exhibit various intermediate phases including orthorhombicgamma and tetragonal phases. Superconducting transition temperature, Tc, of pure TiZr alloys, increased from 2.7 K to 11.7 K with increasing pressure from 5.4 GPa, and 50 GPa, respectively. Interestingly, the Tc values for hydrogenated samples increased from 3.4 K to 9.4 K at 6 GPa and 32 GPa, respectively, but decreased to 8 K with increasing pressure further to 55 GPa. The Tc values were suppressed under the magnetic field and the critical field for the hydrogenated one is less than the one of pure state at 50 GPa. Our combined results of structure and transport measurements suggest that applying pressure increases the Tc while hydrogen atoms form an irreversible hydride phase and decrease the Tc. The contribution of hydrogen for increasing Tc in transition metals is different from the ones observed in polyhydrides exhibiting near room temperature of Tc under high pressure. 

T00.00320: Micromechanical Computational Framework for Deformation Twinning Curt A Bronkhorst, Tao Jin, Irene J Beyerlein Deformation twinning is an important plastic deformation mechanism for many metallic materials under extreme conditions of loading. We present a novel crystal plasticity finite element framework that accounts for deformation twinning explicitly, and crystallographic slip. Within this computational framework, deformation twins are treated as weak discontinuities embedded within individual finite elements, such that a jump in the velocity gradient field is introduced between the twinned and untwinned crystalline regions, taking into account compatibility and traction continuity conditions at the interface between these two regions. The deformation gradient is multiplicatively split into elastic and plastic parts in the untwinned region, as is customary in finitedeformation crystal plasticity formulations. A different multiplicative decomposition of the deformation gradient into elastic, plastic (slip), and twinning parts is adopted in the twinned region, allowing deformation twinning to be accounted for as an additional mode of plastic deformation. A stochastic model is used to predict twin nucleation at grain boundaries, and the evolution of the length and thickness of the twinned region under deformation is taken into account. The linearization of the singlecrystal plasticity model, is required in order to enforce traction continuity at the interface between the twinned and untwinned regions using a Newton iterative scheme. Simulations of the initiation and propagation of {1012} tensile twins in hexagonal close packed (HCP) titanium are presented to demonstrate the capabilities of the proposed computational framework. 

T00.00321: FirstPrinciples Molecular Dynamics Simulations of the Spontaneous Freezing Transition of 2D Water in a Nanoslit Jian Jiang, yurui Gao, Weiduo Zhu, Yuan Liu In this work, the spontaneous freezing transition of 2D liquid water within hydrophobic nanoslits is demonstrated for the first time using firstprinciples MD simulations. The liquid water confined to a 6.0 Åwide nanoslit can spontaneously freeze into a monolayer ice consisting of an array of zigzag water chains at 2.5 GPa and 250 K. Moreover, within an 8.0 Åwide nanoslit and at 4.0 GPa and 300 K, a previously unreported bilayer ice forms spontaneously that has a structure resembling that of the double surface layers of bulk iceVII. Notably, both 2D crystalline ices do not obey the ice rule. 

T00.00322: Synthesis of graphene via combustion of acetylene and oxygen gas Catherine Johnson, Everett V Baker, Sean Bailey, Frank Schott, Martin J Langenderfer, William G Fahrenholtz, Jeremy Watts Recent research has shown that ignition of certain fuel rich ratios of acetylene and oxygen gas within a confined chamber will result in solid graphene as a product. Graphene, a single atom thick layer of carbon that is known for its relative strength and electrical properties, is often made via physical exfoliation or one of numerous deposition processes. In contrast, combustion synthesis of acetylene could be a far cheaper and simpler method for graphene production, possibly being only a tenth of the cost compared to current methods of production. This research focused on the mechanism behind graphene formation, observing the flame velocity and combustion pressure of varying oxygen:acetylene ratios in order to determine ideal conditions for graphene formation. These results will be used to compare the flame front velocity of a stochiometric oxygen:acetylene ratio to the velocity of varying oxygen:carbon (O/C) mixes from 0.25 to 0.75 O/C. This flame velocity data combined with graphene production tests using the same O/C ratios will aid in determination of the most efficient conditions for synthesis of graphene via hydrocarbon combustion. 

T00.00323: Laser Induced shock propagation in bulk Transparent glass media Sai Shiva S, Nagaraju Guthikonda, SASANK S GUNDU High energy laser pulses are replacing the traditional hammers, shock tubes and gas guns to induce impulses that are sufficient to compress the medium to extreme states by launching shockwaves capable of inducing phase transitions in the medium. We present the shockwave evolution during ns laser pulse interaction with a transparent BK7 glass of dimensions 50 mm × 50 mm × 15 mm. The input laser pulse energies were varied over 500 to 2000 mJ resulting in intensities of 20 – 100 GW/cm^{2}. Due to the transparent nature of the BK7, two different shockwaves one from the interface and the other from selffocused damage track within the bulk of the medium were observed. The shockwaves from the interface propagated along the laser propagation (longitudinal) direction with a velocity of 6.38 – 6.91 km/s. While the shockwaves from the selffocused damage track travelled in the transverse direction. With increasing laser pulse energy, an interesting exchange between the longitudinal and transverse shockwaves is observed. 

T00.00324: Molecular and Nanoscale Anisotropic Shock Response Mechanisms of Aramid Fibers Emily Gurniak, Subodh C Tiwari, Sungwook Hong, Aiichiro Nakano, Rajiv K Kalia, Priya Vashishta, Paulo S Branicio Aramid fibers are used in a wide range of applications due to their low density, high strength, and shock resilience, which originates from the properties of poly(pphenylene) terephthalamide (PPTA). Notwithstanding their wide applications, e.g., in Twaron, Kevlar and other highperformance fabrics, there are still gaps in the understanding of the intrinsic deformation mechanisms of this material under shock loading. Here, we perform molecular dynamics simulations with a reactive force field, ReaxFF, to characterize the PPTA shock response for loading along the [100] and [010] directions, perpendicular to the polymer backbone/fiber axis. The plastic deformation for shocks along [100] preserves hydrogen bonding, while the shock is released with the generation of shear bands, where the PPTA structure becomes planarized. Amorphization is induced for shocks along [010] promoting massive hydrogen bond scission. These shock regimes occur until crosslinks between polymer chains are triggered, starting at U_{p} = 2.18 km/s for [010] direction and U_{p} = 2.46 km/s for [100] direction. These results demonstrate the underlying molecular and nanoscale deformation mechanisms of PPTA furthering our understanding of shockloading of strong, highperformance polymers. 

T00.00325: Power of Sulfur – Chemistry, Properties and Laser Ignition Studies of Energetic PerchlorateFree 1,3,4Thiadiazole Nitramines. Michael Gozin, Lei Zhang In this work, a series of new sulfurcontaining energetic materials (SEMols) was synthesized on a basis of a novel explosophore. The structures of new SEMols L1, L4, and their Cu derivatives C6, C7, and C9 were determined by spectroscopic techniques and Xray crystallography. Following structural characterization, thermal analyses and safety studies of L1, L4, and C7 were performed. Comparing thermal decomposition profiles of L1 and L4 with their sulfurfree analogs, we found that the incorporation of sulfur atoms into structures of energetic molecules significantly improved their thermostability. With respect to the sensitivity to impact, friction, and electrostatic discharge, SEMol L1 exhibited properties of a secondary explosive, while L4 and complex C7 showed properties between the primary and secondary explosives. The perchloratefree complex C7 was evaluated as a lowpower laser ignitable material, exhibiting an ignition delay time of 11 ms and a threshold irradiation energy of 12.0 mJ at 915 nm. Based on our experimental observations, we hypothesized that the laser initiation mechanism of C7 is photothermal. Utilizing TDDFT calculations, we proposed that the ignition process begins with sequential multiphoton absorption and proceeds through the excitation of molecular vibrations, which lead to a drastic increase in the temperature of the molecules at the irradiation spot, which is followed up with an avalanchetype bond dissociation process in the rest of the material. We also performed abinitio molecular dynamics calculations to explore the advancement of the decomposition process at different temperatures. The introduction of new sulfurcontaining energetic materials into the family of laserignitable materials should result in a significant expansion of the currently available molecular design options for laserignitophores, and lead to the development of new materials with advantageous performance and safety properties. 

T00.00326: Micromechanics of Ductile Damage during High Triaxiality Loading of a Refractory Metal Curt A Bronkhorst, Hansohl Cho, Peter Marcy, Scott Vander Wiel, George T Gray Accurately representing the process of porositybased ductile damage in polycrystalline metallic materials via computational simulations remains a significant challenge. The heterogeneity of deformation in this class of materials creates the conditions for the formation of a damage field. A technique of softcoupled linkage between a macroscale damage model and micromechanical calculations of a suite of polycrystal realizations of a representative BCC tantalum with nonSchmid effects is presented. The macroscale model, which accounts for ratedependence and microinertial effects, was used to model two plate impact experiments and predict the point in the loading profile when porosity is initiated. A singlecrystal model is used for polycrystal calculations of statistically representative microstructures of the tantalum material subjected to the extreme loading conditions informed from the macroscale calculations. This provides localscale stress conditions for porosity initiation within the polycrystalline network. The results suggest that the nonSchmid effects significantly influence the local stress conditions across grain boundaries and triple junctions and stress at grain boundaries depend upon orientation of each boundary with respect to the shock direction. Results also suggest that the von Mises stress and triaxiality at the grain boundaries and the grain boundary triple lines are highly variable but the variability is diminished with distance to the grain center. 

T00.00327: SHOCK COMPRESSION OF CONDENSED MATTER


T00.00328: Deep reinforcement learning optimizes graphene nanopore geometry for efficient water desalination. Zhonglin Cao, Yuyang Wang, Amir Barati Farimani Twodimensional nanomaterials, such as graphene, have been extensively studied because of their outstanding physical properties. Structure and topology of nanopores on such materials are for their performances in realworld engineering applications, like water desalination. However, discovering the optimal geometry for nanopores often involves very large number of experiments or simulations which are expensive and timeconsuming. In this work, we propose a deep reinforcement learning (DRL) framework for discovering the most efficient graphene nanopore for water desalination. Using the DRL framework, we rapidly create and screen thousands of graphene nanopores with different geometries and select the best performing ones. Molecular dynamics (MD) simulations on promising DRLcreated graphene nanopores show that they have higher water flux while maintaining rival ion rejection rate compared to the normal circular nanopores. Irregular shape with rough edges geometry of AIcreated pores is found to be the key factor for their superior water desalination performance. Ultimately, this study shows that DRL can be a powerful tool for nanomaterial design and screening. 

T00.00329: Source Position Sensitivity of a Coaxial HPGe Detector via Machine Learning Randall Gladen, Varghese A Chirayath, Sima Lotfimarangloo, Jack Driscoll, Alexander Fairchild, Ali R Koymen, Alex H Weiss Spatial localization of gamma sources is often attained by using absorbing collimators or specificallyconstructed detectors. If an estimate of the location of the gamma source could be determined using a standard portable Germanium (HPGe) detector without additional collimation, it would improve the efficiency of nuclear safety inspections in detecting illicit gammaemitting material. Here, we propose to utilize machinelearningbased approaches to derive the direction of the gamma photon from the shape of the pulses produced by the HPGe detector. This shape is reflective of the location at which the photon deposits energy in the coaxial detection volume, thus providing a relationship with the direction of entry of the gamma photon. The shapedirection relationship is utilized by training a selforganizing map to develop patterns specific to the location of the gamma source. We use these maps to train another simple network to map these shape patterns to the direction of the gamma source and show that coaxial HPGe detectors are capable of estimating the direction of a gamma source. 

T00.00330: Applying Differentiable Programming to Kinetic Plasma Physics Simulations Archis Joglekar, Alexander G Thomas Plasma supports collective modes and particlewave interactions that leads to complex behavior in fusion energy, and other applications. While plasma can sometimes be modeled as a charged fluids, the VlasovPoisson system of partial differential equations provides a description that is useful towards the study of nonlinear effects in the higher dimensional momentumposition phasespace that describes the full complexity of plasma dynamics. By constructing a VlasovPoisson solver using a differentiable framework, we are able to perform gradientbased optimization of arbitrary functions of the simulation results with respect to input parameters. We validate the methodology and implementation by rediscovering resonances in the wellunderstood linear regime. Then, we use our solver to learn the parameters to a forcing function that reveal new nonlinear effects in finitelength electrostatic plasmawave propagation. We also discuss the effect of neuralreparameterization of the inputs on the optimization process. 

T00.00331: A comparison of machine learning/deep learning algorithms for the classification and prediction of cancerous tumors Solene L Bechelli, Jerome P Delhommelle With cancers being one of the leading causes of death, research in this field has considerably increased over the past decades. One way to improve the recovery chances in patients is its early detection. Moreover, with the improvements of Machine Learning algorithms, the determination of early diagnosis is made easier. In this study, we compare the performance of different algorithms from Linear regression and classification tree to pretrained models such as ResNet50 or VGG16. In addition, we develop our own Convolutional Neural Network. We show that in addition to a similar performance in terms of accuracy, our CNN model provides much faster prediction than the pretrained models. 

T00.00332: Machine Learning: the ultimate tool for predicting the fascinating properties of Active Matter. Ilham Essafri, Carloine Desgranges, Jerome Delhommelle Active systems are groups of interacting, selfdriven "machines" that selforganize on multiple scales with no predefined and in the presence of noise. Recently with the development of new algorithms and new open areas to predict equations from datasets, we've been able to think about the possibility of determining the governing equations for such complex phenomena. In this work, we use Machine learning to predict the dynamic behavior of these active systems. Our aim is to develop artificial intelligence algorithms to predict the fundamental equations that describe the behavior of active matter. Our results show that we can predict equations of motion for several types of timeseries data from simulations, from numerical data, and from microscopy video recorder images. Interestingly, our predicted equations have a low level of complexity and a reduced number of parameters. This provides a combined computational and machine learning framework that sheds light on the physical underpinnings of active systems and provides suggestions on how to engineer the assembly of smart active materials. 

T00.00333: A machinelearned molecular dynamics modeling of the spontaneous rollingup and assembly of MoS_{2} monolayers designed with vacancy defects Akram Ibrahim, Yelda Kadioglu, Can Ataca Monosulfur vacancy (V_{S}) and disulfur vacancy (V_{S2}) are two types of point defects commonly observed in chemically grown MoS_{2} monolayers. These defects can provide opportunities to tune the physical and chemical properties of such twodimensional materials. In this study, we model the spontaneous curling of freestanding MoS_{2} monolayers engineered with V_{S} and V_{S2} defects using molecular dynamics (MD) driven by a neural network potential (NNP). The NNP is trained on Density Functional Theory (DFT) calculations and shows an excellent agreement on the prediction of structural and vibrational properties while retaining a linear scaling with the system size. We first use the cluster expansion (CE) method to identify the ground state crystal structures at the different S vacancy concentrations. The NNP is then used to run largescale MD simulations of MoS_{2} sheets of various sizes for the vacancy concentrations of interest. The curling process is found to be mainly dominated by the vacancy concentration, having either V_{S} or V_{S2} defects and the tailored MoS_{2} sheet size. It is also found that when the dimension is larger than an upper threshold, the two free ends can sew up forming onedimensional MoS_{2} single/multilayer nanotubes. 

T00.00334: Machine LearningDriven Scanning Probe Microscopy for Ferroelectric Domain Writing Yongtao Liu, Kyle Kelley, Maxim Ziatdinov, Sergei V. Kalinin Increasing research interests in ferroelectric memory give rise of efforts in investigating ferroelectric domain writing at the nanoscale level. Given the requirements of ferroelectric memory are generally operating time, bit size, and retention time, studies of domain writing mainly focus on domain size and stability. Scanning probe microscopy (SPM), due to its capability of visualization and control of ferroelectric domains at the nanoscale level, has been extensively used to investigate domain writing in relation to writing bias parameters, such as biasing time, bias voltage, so on. However, until now, most exploration of domain writing parameters depends on humanbased decision making, i.e., operators determine the parameters for the next iteration of the domain writing process according to the previous experiment. In this work, we explored the domain size and shape in relation to the writing voltage and writing time using a machine learning (ML) driven SPM workflow, where an ML algorithm is used to control the SPM for ferroelectric domain writing and visualization. In this workflow, a group of initial writing parameters is first used to write domain structure in a ferroelectric BiFeO_{3} thin film. The written domain structure is extracted by a threshold filter from the piezoresponse force microscopy image to analyze the domain shape and size. Then, the ML algorithm will optimize the writing parameters according to the previous domain structure. 

T00.00335: Accelerating Exploration in Plasma and Radiation Physics using Bayesian Optimization Jeremy Marquardt, Stylianos Chatzidakis, Allen L Garner, James R Prager Modern scientific and physical experiments are frequently complex and multidimensional in nature, especially with the recent big data explosion. However, the exploration of such a large hyperspace to identify the optimal solution is still guided by methods based on experience and intuition similar to those applied for simpler onedimensional experiments. Unfortunately, despite the recent advances in computing and machine learning, optimization tools to accelerate and guide experimental design are not widely understood and therefore underutilized. In this work, we develop and explore a novel Bayesian optimization methodology and apply it to navigate the large multidimensional space of modern plasma and radiation physics to adaptively design the next experiment that will bring us closer to the optimal solution. The foundations, construction, and methods of Bayesian Optimization are provided in this work. We further demonstrate the potential use of Bayesian optimization by (1) guiding parameter optimization for atmospheric pressure, pulsed plasmas for inactivating microorganisms and (2) accelerating the detection of a hidden radiation source to enhance emergency response and nuclear nonproliferation capabilities. Even with limited data, our approach appears to successfully identify the parameters needed to perform the next experiment that will move the solution closer to the optimal. We show that after only a few iterative steps, the algorithm can correctly reach the optimal solution and accelerate the experimental process, while decreasing cost and time. 

T00.00336: Enabling Electrically Controllable Nanophotonic Structures Using 2D Materials Safura Sharifi, Yaser Banadaki, Georgios Veronis The rapid development and unique properties of twodimensional (2D) materials enable them to become intriguing candidates for future photonic applications. We propose new aperiodic multilayer structures based on 2D materials to enable fully electrically controllable switchability. The structure is composed of alternating layers of graphene and hexagonal Boron Nitride (hBN) sandwiched between two layers of Tungsten Disulfide (WS2). This aperiodic multilayer structure provides spectraaltering properties similar to those of more complex and harder to fabricate two or threedimensional structures, demonstrating a proof of concept to design and implement more complex structures. We use a hybrid optimization method, consisting of a microgenetic global optimization algorithm coupled to a local optimization algorithm, to find the optimum thicknesses of the layers in the aperiodic multilayer structure in order to maximize the absorptance to the excellent value of unity at a prespecified wavelength, under zero bias condition. By changing the chemical potential, we can manipulate the refractive index of Graphene and thus have control over absorption. The structure is promising for various applications, such as spacecraft thermal control systems (TCS). 
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T00.00337: Crystal Structure Prediction from AtomicResolution Electron Microscopy Images using Deep Learning Buduka Ogonor, Maria K Chan, Joydeep Munshi Accurate identification and classification of crystal structures, in many technological applications, is one of the first steps towards extracting useful information from atomicresolution images. However, identifying the structural information from these images using traditional realspace approaches, such as finding local intensity maxima and template matching is challenging due to the lack of robustness of the image analysis methods. To this end, the development of a fast and automated structure prediction tool using AI/ML will play an important role in improving the prediction accuracy. Here, we discuss a proofofconcept study to demonstrate performance of a deep neural network leveraging the transfer learning approach to learn different crystal phases from real space highangle annular darkfield scanning transmission electron microscopy (HAADFSTEM) images. To this end, we take around 200,000 simulated real space HAADFSTEM images, collected and preprocessed from Atomagined dataset (https://github.com/MaterialEyes/atomagined), for the deep learning training. Finally, we test the performance and accuracy of the network on both simulated test dataset and experimental images curated from existing literature. 

T00.00338: Classifying and Categorizing Lunar Craters using Convolutional Neural Networks Jamie Johnston, Matthew E Caplan Traditionally, lunar crater counting has been done by visual inspection of images of the moon’s surface. This method is time consuming and has poor interrater reliability for smaller craters. Automating this process using a Convolutional Neural Network (CNN) greatly improves the speed and reliability at which surface features can be detected and classified. Using available high resolution Digital Elevation Model (DEM) images from the Lunar Reconnaissance Orbiter (LRO), we train a CNN to identify craters and classify them based on the slope of their ejecta blanket. Presently the population of small impactors is not well understood but improved detection of the smallest craters can constrain the size distribution of asteroids in the solar system. Additionally, we intend to search for small craters with novel features that are inconsistent with traditional asteroid impacts to potentially constrain the moon’s interaction history with MACHO dark matter from the Galactic halo. 

T00.00339: Discovering Sparse Interpretable Dynamics from Partial Observations Peter Y Lu, Joan Arino Bernad, Marin Soljačić Identifying the governing equations of a nonlinear dynamical system is key to both understanding the physical features of the system and constructing an accurate model of the dynamics that generalizes well beyond the available data. In many instances, this problem is further compounded by a lack of available data and only partial observations of the system state, e.g. forecasting fluid flow driven by unknown sources or predicting optical signal propagation without phase measurements. We propose a machine learning framework for discovering these governing equations using only partial observations, combining an encoder for state reconstruction with a sparse symbolic model. The entire architecture is trained endtoend by matching the higherorder symbolic time derivatives of the sparse symbolic model with finite difference estimates from the data. Our tests show that this method can successfully reconstruct the full system state and identify the equations of motion governing the underlying dynamics for a variety of ODE and PDE systems. 

T00.00340: A MeshFree CurvatureBased Approach to Analyzing the Mechanics of Aortic Diseases Janet Kang, Luka Pocivavsek, Kameel Khabaz, Gordon Kindlmann Aortic dissections present a mechanical problem of fracture in the aortic wall. The mechanism by which this occurs is unclear but is strongly influenced by the aorta's geometric complexity. As such, analyzing aortic geometry can enhance our understanding of its mechanical state. Our group has established a curvaturebased geometric approach to analyzing the stability of aortic dissections. However, the calculation of curvature on the aortic surface requires the creation of a threedimensional mesh, a process that is timeconsuming and laborintensive. We have developed a novel approach to measure curvatures on the aortic surface directly from raw imaging data, eliminating the need for meshing. By creating a model of the aorta from an isosurface of equal intensity values on computed tomography (CT) images and reconstructing derivatives on the neighboring data points, we extract the principal curvatures of a local region on the aortic surface. This new method allows us to connect aortic geometry with aortic stability in a more efficient process, providing possible avenues for future clinical applications. 

T00.00341: Defects design in 2D materials via highthroughput calculation and machine learning Pengru Huang, Miguel Dias Costa, Ruslan Lukin, Nikita Kazeev, Andrey Ustyuzhanin, Alexander Tormasov, Castro Neto Antonio Helio, Konstantin Novoselov Employing high throughput DFT calculations, we study the crystal structure, stability, and electronic structures of defects in 2D materials such as hexagonal boron nitride and transition metal dichalcogenides. The interaction of defects was evaluated by comparing the formation energies of defect complexes and individual defects. A meanfield theory model was constructed to understand the interaction dynamics of defects. Machine learning models were trained to predict the stability and electronic properties of defects. 

T00.00342: Development and Use of a Neural Network for Optimizing Output of Accelerator with Large ControlParameter Space Nicholas Valverde, Qing Ji, Alexander Scheinker, Arun Persaud, Steven M Lund Accelerator systems with a large controlparameter space can be difficult to optimize. We report ongoing work to develop and train a neural network to act as a highfidelity surrogate model. This model is used to find optimal parameter settings for given performance metrics. The accelerator system used is the Neutralized Drift Compression ExperimentII (NDCXII). It is a high intensity ion induction linac at Lawrence Berkeley National Laboratory used to accelerate, shape, and compress a bunch of He^{+} ions^{ }. It has a 1m long drift section between the final focusing solenoid and target that is filled with plasma to neutralize beam spacecharge in the final stage of the pulse compression to enable higher intensity ontarget. NDCXII is capable of delivering 0.7J/cm^{2 }within a ~1mm diameter spot ontarget by compressing and accelerating an initial ~600ns, 135KeV pulse to ~1ns, 1MeV ontarget. Approximately 40 parameters are used to vary the system with detailed simulations used to guide machine tuning. A NN consisting of dense fully connected layers is trained using experimental and simulation data. Here we report on the fidelity of the NN and progress towards increasing delivered fluence along with further experimental applications. 

T00.00343: Efficient Characterization of Quantum Evolutions via a Recommender System Priya Batra We demonstrate characterizing quantum evolutions via matrix factorization algorithm, a particular type of the recommender system (RS). A system undergoing a quantum evolution can be characterized in several ways. Here we choose (i) quantum correlations quantified by measures such as entropy, negativity, or discord, and (ii) statefidelity. Using quantum registers with up to 10 qubits, we demonstrate that an RS can efficiently characterize both unitary and nonunitary evolutions. After carrying out a detailed performanceanalysis of the RS in twoqubits, we show that it can be used to distinguish a clean database of quantum correlations from a noisy or a fake one. Moreover, we find that the RS brings about a significant computational advantage for building a large database of quantum discord, for which no simple closedform expression exists. Also, RS can efficiently characterize systems undergoing nonunitary evolutions in terms of quantum discord reduction as well as statefidelity. Finally, we utilize RS for the construction of discord phase space in a nonlinear quantum system. 

T00.00344: Disentangling Intracellular Behavior from Extracellular Data Andre Archer, Taylor Nichols, Niall Mangan, Danielle TullmanErcek Bacteria can utilize a biodiesel waste product, glycerol, to produce 1,3propanediol (1,3PDO), a common commercial solvent. To study the viability of 1,3PDO producing bacteria, the cell membrane transport of reactant species and the invivo kinetics of the pathway enzymes (DhaT & DhaB) need to be quantified. The kinetics of purified DhaT have been studied, but the reaction environment and kinetics in cells may differ. Additionally, the kinetics of the DhaB enzyme and cell membrane transport mechanisms of the reactants are undetermined. 

T00.00345: Solving the inverse problem of timeindependent Fokker–Planck equation with a selfsupervised neural network method Wei Liu, Hwee Kuan Lee, Connie Khor Li Kou, Kun Hee Park The Fokker–Planck equation (FPE) has been used in many important applications to study stochastic processes with the evolution of the probability density function (pdf). Previous studies on FPE mainly focus on solving the forward problem which is to predict the timeevolution of the pdf from the underlying FPE terms. However, in many applications the FPE terms are usually unknown and roughly estimated, and solving the forward problem becomes more challenging. In this work, we take a different approach of starting with the observed pdfs to recover the FPE terms using a selfsupervised machine learning method. This approach, known as the inverse problem, has the advantage of requiring minimal assumptions on the FPE terms and allows datadriven scientific discovery of unknown FPE mechanisms. Specifically, we propose an FPEbased neural network (FPENN) which directly incorporates the FPE terms as neural network weights. By training the network on observed pdfs, we recover the FPE terms. Additionally, to account for noise in realworld observations, FPENN is able to denoise the observed pdfs by training the pdfs alongside the network weights. Our experimental results on various forms of FPE show that FPENN can accurately recover FPE terms and denoising the pdf plays an essential role. 

T00.00346: DATA SCIENCE


T00.00347: Bohr Adapted James the Psychologist's, "Complementarity" for Measurement in Quantum Mechanics: James's works for QM, Bohr's Does Not Douglas M Snyder


T00.00348: HISTORY OF PHYSICS


T00.00349: Experimental tests of the twin paradox using extraterrestrial clocks Donald C Chang We know modern physics has two cornerstones: quantum mechanics and the special theory of relativity. Are these two theories consistent with each other? The key question here is that: Is the vacuum between matters empty or not? The principle of relativity (PR) requires the vacuum to be empty; otherwise, the vacuum will become a resting frame in our universe. Then, one can use this resting frame to determine which inertial frame is stationary and which frame is moving. However, the assumption of an empty vacuum is in contradiction with our understanding in quantum mechanics, which regards the vacuum as the ground state of the quantum system. There is plenty of evidence indicating that the vacuum is not empty. Thus, it is very much worthwhile to reinvestigate an old question: Can any inertial frame be regarded as a stationary frame? It had been pointed out long time ago that the PR will cause a twin paradox. In the previous experiments that supported the PR, they only demonstrated that time dilation is real, but did not test whether any inertial systems can be chosen as the stationary frame. To overcome their problems, we propose here to use two identical clocks placed separately on Earth and Mars to test the twin paradox. The details of our experiment design will be presented in this paper. 

T00.00350: Physics in Turkey Cooking: Revisit the Panofsky Formula Lisa R Wang, Yifei Jenny Jin In 2008, Panofsky gave an empirical formula T = (1/1.5)W^{2/3}, for turkey baking time, T, in hours versus turkey weight, W, in pounds, the socalled Panofsky formula. Compared to the previously existing recipes based on the simple linear relationship between turkey weight and baking time, the Panofsky formula provides a more accurate estimate for the baking time. In this work, we conduct a comprehensive study of the turkey baking process, which leads to the mathematical derivation of the Panofsky formula under some approximations. We also generalize the Panofsky formula to define a general formula, T = (1/P)W^{2/3}, where P is defined as the Panofsky Constant. Under the spherical approximations, we then apply an accurate physical solution of the heat transfer equation and use the rigorous solution with numerical methods to study the generalized Panofsky formula and the Panofsky constant. We found that the generalized Panofsky formula can be perfectly applied to all turkey baking scenarios for baking time calculations. Furthermore, we did a careful analysis of the Panofsky constant. The dependency of the new Panofsky constant on the turkeys' thermal properties and other initial baking parameters was carefully mapped out. 

T00.00351: Fundamental Cosmology and Physics Beyond the Standard Model John G Nicholson This is an outrageous hypothetical exploration of what is possible when you expand on some of the principles of physics, for the purpose of explaining some of the biggest questions left in physics. The paper expands on the work of Plato, Newton, Einstein and many others to establish a twopart Universe with one part quantum computational. Thermodynamics is revised accordingly. Information takes it rightful place, where many theoretical models leave it out, as the most critical foundation for cosmology. In the modeling process, a simple pathway to a different and deeper understanding of the problems we have in physics is revealed. The singularity is defined as a transition and a pivot. Dark matter and energy are hypothesized as antimatter held in a separate frame of reference and as a superfluid of negative mass. The real observations are discussed and explained as the hypothesis is applied, including accelerated expansion due to transition. Uncertainty and entanglement are illuminated with the properties of information. 

T00.00352: Robust "AllClear" Forecast of Solar Proton Events with Machine Learning Using McIntosh and Magnetic Classification of Active Regions Russell Marroquin, Viacheslav Sadykov The Increased radiation of Solar Energetic Particles (SEPs) may impact the health of astronauts during space operations and may hinder future space explorations. Solar Proton Events (SPEs) represent a major subclass of SEPs. In this work, the importance of developing "allclear" prediction of SPEs is considered. The project can be divided into three phases: 1)Creation of database. Data containing SEP events based on active regions of the Sun is retrieved using an Application Programming Interface (API) and a data retrieval tool. Data is then converted into a data frame and missing inputs are extrapolated to produce a wholeSun input. 2)Application of Artificial Intelligence to produce prediction. Database is divided into a set of training data and testing data. Machine Learning is applied to an Artificial Neural Network designed for wholeSun input, which is then trained and tested using the respective data sets. 3)Assessing performance. This effort represents an extension of previous "allclear" forecasting analysis (Sadykov et al. 2021) using data from 2010 to 2020. To produce a more robust "allclear" forecast, we increase the input data with a new range spanning 1996 to 2020. We will discuss the performance of the developed AI approach against current operational forecasts. 

T00.00353: Very Light Sterile Neutrinos at NOvA and T2K Giancarlo Jusino Sanchez Neutrinos are elusive particles with several outstanding questions such as: Why are they so light? What extension to the Standard Model can explain their mass? What role do they play in the matterantimmater asymmetry in the observable universe? Another such question is whether neutrinos that don’t interact via the weak force exist. These particularly elusive neutrinos, called sterile neutrinos, could be responsible for some of the anomalies and discrepancies seen in experiments like MiniBooNE, LSND, and more recently the longbaseline experiments NOvA and T2K. We perform a hypothesis test to determine whether a very light sterile neutrino significantly eases the tension between the NOvA and T2K measurements. To carry out this test, we develop simulations that replicate the results from NOvA and T2K given their most recent data. We then perform a jointfit to see how the sterile neutrino model performs. Although the results point at a sterile neutrino being unlikely, we can place new constraints on the sterile parameters. 

T00.00354: Solid electrolyte behaviour in K_{3}H(SeO_{4})_{2 }studied by defect interaction. Oscar S HernandezDaguer This paper explores and proposes a structureconductivity correlation in the K_{3}H(SeO_{4})_{2} (TKHSe) crystal. The thermal transformation which appears around T_{p} = 388 K is endothermic in addition to showing a slight weight loss. The enthalpy (ΔH) and weight loss changes on successive heating and cooling runs through T_{p} slightly decrease, showing that T_{p} marks the onset of a slow thermal dehydration of TKHSe. The step change in the dc ionic conductivity of three orders of magnitude is also reduced slightly on successive heating and cooling runs. Our results then show that the observed ΔH at T_{p} is due to a firstorder phase transition of the orderdisorder type with that occurs simultaneously with a slow dehydration process. Moreover, the observed decrease of the magnitude of conductivity on successive thermal runs is a consequence of decomposition at the surface of the TKHSe grains, but the jump in conductivity is only a consequence of the orderdisorder transition in the TKHSe phase that remains inside the grains. The observed firstorder phase transition that leads to the fastion conducting phase in TKHSe above T_{p} is studied by a trial free energy density. By properly adjusting the model parameters, an abrupt change of disordering mobile ion concentration, c'(T), is predicted at a transition temperature, T_{p}. The temperature dependence of the dcconductivity, σ, is well fitted to the c´(T) equilibrium configuration obtained from the trial free energy function. Using a trial free energy density model was possible to fit the Phase II and the jump in conductivity curves for K_{3}H(SeO_{4})_{2}. This fact shows the conductivity phenomena in this compound is due to solidsolid phase transition. And why the most known models, just can't explain, based on the crystal structure satisfactorily the high proton conductivity phase. Whereby we propose; more than one mechanism or interaction is required to fully explain the conductivity phenomena in phase I and II in the K_{3}H(SeO_{4})_{2}. 

T00.00355: Local and Travelingwave Modes of Vibrations of Protons and Oxygens in a Finite Volume of Melted Ice in Hexagonal Close Packed Lattice Bin B Jie, Cindy Tianhui Jie We started water study for the 2013 Annual National Fall Meeting of the Physical Society of the PRC (People’s Republic of China), at the Sah PenTung 111th Anniversary Symposium on the past and future of Microelectronics Technology, to supplement the Plenary when a more knowledgeable speaker Jack Sun (TSMC CTO) was recruited. We thought Water Physics was well known 55 years ago when Shockley showed Fig 5.1 in Hannay’s ACS Monograph No. 140 (1959) the Arrhenius plot of pH of liquid water (0–100^{o}C, 540meV thermal activation energy) next to semiconductor Ge (780meV) and Si (1178meV). Our mentor Chihtang Sah decided to delay retiring from his career in transistor physics and manufacturing engineering to find out why the electrical mobilities of the negative hydroxide ion OH^{– }and positive hydronium ion H_{3}O^{+} are many times higher than the impurity ions in pure water (Na^{+}, K^{+}, Ca^{2+}, Cl^{–}, I^{–}, F^{–}). We found the Melted Ice Hexagonal Close Packed Lattice excellently modeled the liquid pure water as a Protonic Semiconductor. We also discovered the selfinduced protonic (proton and prohol) traps via absorbing the local and traveling vibration modes of protons and prohols to transport the thermal activation energy in liquid pure water from the experimental proton and prohol mobilities. 

T00.00356: Phase transition and visible light driven enhanced photocatalytic activity of EuNi codoped bismuth ferrite nanoparticles Subhra S Brahma Bismuth Ferrite (BiFeO_{3}), as a roomtemperature multiferroic material has garnered quite attention of the physicists. The lowband gap and high visiblelight absorption of BiFeO_{3} can be exploited for photocatalytic applications for the degradation of industrial pollutants. With partial substitution of ‘Eu’ and ‘Ni’ at the ‘Bi’ and ‘Fe’ site of BiFeO_{3 }respectively, there happens to be a structural distortion from rhombohedral (R3c) to a mixed phase comprising of orthorhombic (Pnma) and rhombohedral (R3c) phase, confirmed from Rietveld and Raman analysis. We observe that EuNi doped BiFeO_{3} nanoparticles degrade 2nitrophenol (50 mg/L) to 99.26 % within 2 hours of irradiation as compared to 69 % for pure BiFeO_{3}. The creation of deep impurity states below the conduction band owing to the replacement of Fe^{3+} with Ni^{2+}, decreases the band gap from 2.17 eV to 2.12 eV and also act as trap centres for charge carriers, thus preventing recombination and enhances the photocatalytic activity. Adsorption of pollutants on the surface of photocatalyst is more for codoped nanoparticles, owing to its higher porosity as well as increased surface area, hence enhancing photocatalytic activity. 

T00.00357: Collective excitations in ultrathin metasurfaces of selfassembled carbon nanotubes Igor V Bondarev, Chandra M Adhikari Thin and ultrathin parallelaligned singlewall carbon nanotube (SWCN) arrays and films are currently in the process of rapid experimental development[1,2]. Selfassembled quasiperiodic SWCN films are shown experimentally to exhibit extraordinary optoplasmonic properties[1]. Here we study theoretically the intrinsic collective quasiparticle excitations responsible for the inplane electromagnetic (EM) response of ultrathin planeparallel homogeneous periodic SWCN arrays and weakly inhomogeneous SWCN films[3]. We show that the real part of their inplane EM response in the CN alignment direction exhibits a negative refraction (NR) band near a quantum interband transition of the constituent CN. In this direction alone, the film behaves as a hyperbolic metasurface while being a featureless dielectric in the perpendicular direction. We study how one can tune the properties of these highly anisotropic metasurfaces. We show that by decreasing the SWCN diameter one can push their onedimensional NR band into the visible region and using weakly inhomogeneous multitype SWCN films broadens its bandwidth. – [1]J.A.Roberts, et al., PR Appl. 14, 044006 (2020); Nano Lett. 19, 3131 (2019); [2]W.Gao, et al., ACS Photon. 6, 1602 (2019); [3]I.V.Bondarev & C.M.Adhikari, PR Appl. 15, 034001 (2021). 

T00.00358: Programmable Droplet Manipulation and Wetting with Soft Magnetic Carpets Ahmet F Demiroers The ability to regulate interfacial and wetting properties is highly demanded in antiicing, antibiofouling, medical and energy applications. Recent work on liquidinfused systems achieved switching wetting properties, that allow to turn between slip and pin states. However, patterning the wetting of surfaces in a dynamic fashion still remains a challenge. In this work, we use programmable wetting to activate and propel droplets over large distances. We achieve this with liquidinfused soft magnetic carpets (SMC) that consists of pillars that are responsive to external magnetic stimuli. Liquid infused SMCs which are sticky for a water droplet become slippery upon application of a magnetic field. Application of a patterned magnetic field results a patterned wetting on the SMC. A travelling magnetic field wave translates the patterned wetting on the substrate, which allows droplet manipulation. The droplet speed increases with an increased contact angle or with the droplet size, which offers a potential method to sort and separate droplets with respect to their contact angle or size. Furthermore, programmable control of the droplet allows us conducting reactions by combining droplets loaded with reagents. Such ability of smallscale reactions on SMCs has the potential to be used for automated analytical testing, diagnostics and screening with a potential to reduce the chemical waste. 
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T00.00359: Experiment and Theoretical Analysis of Locally Nonchaotic MolecularSized OutwardSwinging Gate Yu Qiao, Zhaoru Shang, Rui Kou We investigate the concept of molecularsized outwardswinging gate. Our theoretical analysis, Monte Carlo simulation, and direct solution of the governing equations all suggest that across such a gate, under the condition of local nonchaoticity, the probabilities of particle crossing are unequal in the two directions. It was confirmed by an experiment using a nanoporous membrane onesidedly surfacegrafted with bendable organic chains. Remarkably, through the membrane, gas spontaneously and repeatedly flew from the lowpressure side to the highpressure side, clearly demonstrating an asymmetric gas permeability. We show that while this phenomenon is counterintuitive, it follows the basic principle of thermodynamics, as entropy remains maximized. What makes the system unique is that the locally nonchaotic gate interrupts the probability distribution of the local microstates, and imposes additional constraints on the global microstates, so that entropy reaches a nonequilibrium maximum. Such a mechanism is fundamentally different from Maxwell’s demon, and is consistent with microscopic reversibility. When the local nonchaoticity is lost, the gate would converge to the classical systems, such as Smoluchowski’s trapdoor and Feynman’s rachet. 

T00.00360: Probing the molecular response to transient electric field at the interface with voltagejump 2DIR experiment Nan Yang Electricfield plays a vital role in modulating stducture and reactivity in biochemical systems. Probing the electricfield in proteins with Stark reporters has became a widely addpoted approach in vibrational spectroscopy which also provides structral information about the system of interest. In addition, 2DIR offers dynamic structrual information at varioous timescales and recent development of plasmonically enhanced 2DIR experiments has allowed the technique to gain monolayer sensitivity. When the plasmonicaly enhanced 2DIR experiment is carried out at an conductive interface decorated with nitrile electricfield probes, the electric bilayer's response to various electrode potential can be explored. We are currently developing a technique which allows us to alter the potential or electricfield at the interface in nanosecond to microsecond timescale and observe the structral response of molecules on the itnerface. One partcilarly exciting example is the voltage gated ion channls that can be imbeded in a lipid bilayer on the plasmonically active and electrically conductive interface. 

T00.00361: Droplet evaporation on hot microstructured superhydrophobic surfaces: Analysis of evaporation from droplet cap and base surfaces Jiangtao Cheng We experimentally and theoretically investigated evaporation of sessile water droplets on hot microstructured superhydrophobic surfaces in this study. Water droplets of 4 μL were placed on micropillared silicon substrates with the substrate temperature heated up to 120 °C. A comprehensive thermal circuit model is developed to analyze the effects of substrate roughness and substrate temperature on the sessile droplet evaporation. For the first time, two components of heat and mass transfer, i.e., one from the droplet cap surface and the other from the droplet base surface, during droplet evaporation are distinguished and systematically studied. As such, the evaporation rates from both the droplet cap surface and the interstitial liquidvapor interface between micropillars at the droplet base are calculated in various conditions. For droplet evaporation on the heated substrates in the range of 40 °C – 80 °C, the predicted droplet cap temperature matches well with the experimental results. During the constant contact radius mode of droplet evaporation, the decrease of evaporation rate from the droplet base contributes most to the continuously decreasing total evaporation rate, whereas the decrease of evaporation rate from the droplet cap surface is dominant in the constant contact angle mode. The influence of internal fluid flow is considered for droplet evaporation on substrates heated above 100 °C, and an effective thermal conductivity is adopted as a correction factor to account for the effect of convection heat transfer inside the droplet. Temperature differences between the droplet base and substrate surface are estimated to be ~ 2 °C, 5 °C, 8 °C, 12.5 °C and 18 °C for droplet evaporation on substrates heated at 40 °C, 60 °C, 80 °C, 100 °C, and 120 °C, respectively, which elucidates the delayed or depressed boiling of water droplets on a heated rough surface. 

T00.00362: The Effect of Barrier Height on the Design of GaAs/Al_{x}Ga_{1x}As Quantum Cascade Lasers Mary C Lorio, Claire F Gmachl We develop and present guidelines for selecting an optimal barrier height and alloy composition, i.e. the mole fraction x in GaAs/Al_{x}Ga_{1x}As, for Quantum Cascade (QC) lasers. We investigate the effect of barrier height on the figureofmerit (FOM), which is proportional to the laser gain. In a twolevel system, we present a maximum FOM which occurs at x = 0.17. This maximum occurs at zero applied electric field, an energy difference between the first excited and ground states (E_{21}) of 78.2 meV, barrier widths of 200 Å, and a well width of 100 Å. Then, we vary both x and the well width of the twolevel such that E_{21} = 100 ± 2 meV is held constant. The minimum x needed to produce an energy difference E_{21} of 100 meV is x = 0.15 with a corresponding well width of 64 Å. The maximum FOM occurs at this x value. Most importantly, we investigate the optimal barrier height for a threelevel system, the fundamental building block for a laser. We adjust x, the well widths, and inner barrier width so we have the twocoupled QW system needed to achieve this threelevel system. Additionally, we adjust these values such that the energy difference between the second and first excited state, E_{32} = 100 ± 2 meV, and E_{21} = 40 ± 1 meV are constant, as would be required for most laser applications. The optimum parameters to achieve these energy differences are: x = 0.19, well widths of 60 Å, and an inner barrier width of 10 Å. The maximum FOM for E_{32} of 510 ps Å^{2}, or 112872.3 ps meV Å^{2}, also occurs at x = 0.19. This FOM corresponds to a maximum gain of 36.4 cm/kA, a sizeable gain for QC lasers. Therefore, we found an optimal barrier height of x = 0.19 for a threelevel system for a laser omitting photons of 100 meV. This value is almost 50% smaller than the optimal barrier height reported in earlier literature [1] that primarily relied on experimental trialanderror or temperature considerations. As a result, future QC laser design needs to include x as a critical design parameter. 

T00.00363: Efficient and Robust Metallic Nanowire Foams for Deep Submicron Particulate Filtration James Malloy, Alberto Quintana, Christopher Jensen, Kai liu The ongoing COVID19 pandemic has unleashed global disruptions and profoundly changed our way of life. Central to the rapid spread of this respiratory infection is the transmission by airborne viral particles. There is an urgent need for the development of efficient, durable, reusable and recyclable face masks for the deep submicron size range. Here we report the realization of efficient particulate filters using nanowirebased lowdensity metal foams with tunable porosity and density (0.1%30% of bulk density) which combine extremely large surface areas with excellent mechanical properties [1]. The metal foams exhibit outstanding filtration efficiencies (>96.6%) in the PM_{0.3} regime and near 100% efficiency for much of the 0.11.6 micron sized particle range, with a breathability comparable to N95 respirators. The foams can also be easily cleaned, as well as reclaimed and recycled at the end of their life cycle. These attributes make such metal foams promising filters for combating COVID19 and other types of airborne particulates. Our mask design based on such foams has been selected by BARDANIOSH as a Phase 1 Winner of the Mask Innovation Challenge [2]. 

T00.00364: Gain and noise of the Inelastic Cooperpair Tunneling Amplifier (ICTA) Ulrich Martel, Florian Blanchet, Romain Albert, Salha Jebari, Joel Griesmar, Max Hofheinz While Josephson parametric amplifiers have added noise close to the quantum limit, they require a strong microwave pump that can affect the device under test and the generation, routing and filtering of this pump tone require significant hardware overhead. DCpowered amplifiers are much easier to use in that respect but have so far failed to approach the quantum limit because they could not be mapped to a parametric amplification scheme with a wellidentified idler mode. We have demonstrated added noise at the quantum limit within measurement accuracy with the Inelastic Cooperpair tunneling amplifier, a DC powered parametric amplifier with a wellidentified idler mode, based on a voltagebiased Josephson junction where the energy 2eV of a tunneling Cooper pair plays the role of a pump photon. Here, we discuss how design parameters influence the saturation power as well as the highest achievable gain while maintaining quantum limited noise performance. 

T00.00365: Controlling the Speed of an All Optical Switch by Combining Fast and Slow Materials Soham S Saha, Benjamin Diroll, Richard Shaller, Alexandra Boltasseva, Vladimir M Shalaev Alloptical switches control the amplitude, phase, or polarization of light at ultrafast timescales utilizing optical pulses. They operate without the delays of electronic circuits, giving them upto terahertz speeds, and making them essential for both applications like data processing and for fundamental science experiments such as frequency translation or photonic time crystal design. This makes it necessary to understand the role of lightmatter interactions on the dynamic optical response of such systems. 

T00.00366: Electronic structure and estimation of Curie temperature in Ca_{2}BIrO_{6} (B= Cr, Fe) double perovskites shalika R Bhandari, Santosh KC, Sarita Lawaju, Ram Kumar Thapa, Gopi Chandra Kaphle, Madhav Prasad Ghimire We investigate the electronic and magnetic properties of Ca_{2}CrIrO_{6} and Ca_{2}FeIrO_{6} by means of density functional theory. Upon replacement of Os by Ir in Ca_{2}CrOsO_{6}, we found the system to exhibit a stable ferrimagnetic configuration with a band gap of 0.25 eV and an effective magnetic moment of 2.58 μ_{Β} per unit cell. Further when chemical doping is considered by replacing Cr with Fe and Os with Ir, the material retains the insulating state but with a reduced band gap 0.13 eV and an effective magnetic moment of 6.68 μ_{Β }per unit cell. These observed behaviors are noted to be the consequence of the cooperative effect of spinorbit coupling, Coulomb correlations from Cr3d, Fe3d and Ir5d electrons, and the crystal field effect of the materials. This study suggests that by chemical tuning, one can manipulate the band gap and their effective magnetic moment. To check further the suitability and applicability of Ca_{2}CrIrO_{6} and Ca_{2}FeIrO_{6} at higher temperatures, we estimate the Curie temperature (T_{C}) by calculating the spinexchange coupling. We found that our findings are in a valid T_{C} trend similar to other perovskites. Our findings is expected to be useful in experimental synthesis and transport measurement for potential applications in fabrication of modern technological devices. 

T00.00367: Photoinduced spinful excitons in Hubbard systems with magnetic superstructures Constantin Meyer, Salvatore R Manmana The possibility to form excitons in photoilluminated correlated materials is central from fundamental and application oriented perspectives. 

T00.00368: A design strategy for open structures via host–guest–mediated selfassembly Tim Moore, Joshua A Anderson, Sharon C Glotzer Entropically driven selfassembly of hard anisotropic particles, where particle shape gives risetoemergent valency, provides a useful perspective for the design of nanoparticle and colloidal systems. Hard particles selfassemble into a rich variety of crystal structures, ranging in complexity from simple closepacked structures to structures with 432 particles in the unit cell. Entropic crystallization of open structures, however, is missing from this landscape. Here, we report on the selfassembly of a binary mixture of hard particles into an open host–guest structure, where host particles form a honeycomb lattice that encapsulates smaller guest particles [1]. Notably, this open structure forms in the absence of enthalpic interactions and is the first such structure to be observed in a twodimensional athermal system. We discuss the various entropic stabilization effects present in this system and show that certain guest particle sizes can produce reentrant phase behavior. This reentrance suggests the possibility for a reconfigurable colloidal material, and we provide a proofofconcept by showing the assembly behavior while changing the size of the guest particles on the fly. Our findings provide a strategy for designing open colloidal crystals, as well as binary systems that exhibit cocrystallization, which have been elusive thus far. 

T00.00369: MultiLevel Random Telegraph Noise Analysis Protocols based on Machine Learning Algorithms Marcel J Robitaille, Na Young Kim, HeeBong Yang, Lu Wang We present a threestep protocol to analyze multilevel random telegraph noise (RTN) degraded by white noise which we devised to interpret experimental data. Our novel process exploits machine learning techniques of kernel density estimation, Gaussian mixture model, and recurrent neural networks to extract RTN parameters with high accuracy. We successfully decompose multilevel RTN into constituent 2level signals and quantify their transition amplitude and two switching time constants. In order to evaluate the algorithm performance, we generate 330 RTN signals for one, two, and threetrap cases with varying white noise amplitudes. We successfully demonstrate that the accuracy to extract the amplitudes for all generated signals of 20% white noise amplitude is >99% with less than 1 minute of processing by a standard desktop computer. As the white noise level increases, our error for multitrap RTN rises, but its median still lies below 20%. 

T00.00370: Ultrafast thermalization pathways of excited bulk and surface statesin the ferroelectric Rashba semiconductor GeTe Indrajit P Wadgaonkar, Oliver J Clark, Marco Battiato, Jaime Sanchez Barriga In ferroelectric Rashba semiconductors, the study of nonequilibrium properties is particularly attractive. In this work we use timeresolved ARPES to access ultrafast dynamics of bulk and surface Rashba bands after fs optical excitation of GeTe. We observe a complex thermalisation pathway with three distinguishable timescales: intraband thermalisation, interband equilibration and electronic cooling due to electronphonon coupling. The last two timescales show an intriguing temperature dependence. While electronic cooling speeds up with increasing sample temperature, the opposite happens for interband equilibration. To explain such counterintuitive effect we use our novel numerical solver [1,2,3] for the full, nonlinearised, timedependent Boltzmann scattering equation and compute temperaturedependent momentumresolved lifetimes, for 21 electronelectron and 9 electronphonon scatterings. All electronphonon scatterings strengthen with increasing temperature. But counterintuitively, the electronelectron scatterings with largest phasespace get weaker with increasing temperature. We also find these features to survive the removal of spindependent selection rules in the scattering, showing that they are an effect of the Rashba splitting rather than of the wavefunction overlap. 

T00.00371: Triunitary quantum circuits Cheryne Jonay, Vedika Khemani, Matteo Ippoliti We introduce a novel class of quantum circuits that are unitary along three distinct "arrows of time". These dynamics share the analytical tractability of "dualunitary" circuits, while exhibiting distinctive and richer phenomenology. We find that twopoint correlations in these dynamics are strictly confined to three directions in (1+1)dimensional spacetime  the two light cone edges, δx=±vδt, and the static worldline δx=0. Along these directions, correlation functions are obtained exactly in terms of quantum channels built from the individual gates that make up the circuit. We prove that, for a class of initial states, entanglement grows at the maximum allowed speed up to an entropy density of at least one half of the thermal value, at which point it becomes modeldependent. Finally, we extend our circuit construction to 2+1 dimensions, where twopoint correlation functions are confined to the onedimensional edges of a tetrahedral light cone  a subdimensional propagation of information reminiscent of "fractonic" physics. 
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T00.00372: Participation of Women in Science in the Developed and Developing Worlds: Inverted U of Feminization of the Scientific Workforce, Gender Equity and Retention Shobhana Narasimhan


T00.00373: A lateral nanoflow assay for the dimensional and optical metrology of nanoplastics Andrew C Madison, KuoTang Liao, Adam L Pintar, B. Rob Ilic, Craig R Copeland, Samuel M Stavis Polystyrene nanoparticles sorbing and carrying hydrophobic fluorophores are important standards and model nanoplastics with many uses. However, even after decades of development, the variable fluorescence of such nanoparticles is mysterious. To elucidate this variability, we advance a lateral nanoflow assay, integrating complex nanofluidic replicas, superresolution microscopy, and novel statistical analyses to characterize these standards. An elegant scaling of surface forces hydrodynamically automates advection and dominates diffusion of nanoparticles. Steric interaction with the replica structure separates nanoparticles by size, enabling dimensional and optical metrology of single nanoparticles with high throughput. A comprehensive statistical model approaches the information limit of the system, discriminates size exclusion from surface adsorption, and reduces nonideal data to return the diameter distribution to within a rootmeansquare error of 2 nm. A Bayesian statistical analysis of the diameter and intensity of single nanoparticles reveals a powerlaw exponent of nearly four and attributes fluorescivity, an intrinsic property, as the dominant source of variability. These surprising results reset expectations for optimizing and applying nanoplastic standards. 

T00.00374: Existence Of Variations In Human Body Types From Color, Height, Stockyness, Male And Female, Etc But Apparent Sameness in Cognititive System of All Humans From Sameness in Learning To Obtaining Same Mathematical Results: A Cosmological Question Stewart Brekke As a physics teacher in the Chicago Public Schools who has taught in many diversley populated high schools I have observed many similarities in behavior and cognition across ethnic and racial persons. All students of every race or ethnicity, average and higher ability, arrive at the same answer when given the same values for variables and calculating the average speed, using the formula v=d/t. Even in ancient Athens it was recognized that the same reason and logic ability existed in all humans, maleand female, enabling the same answer in geometry using deduction. All students agree that a good looking male or female person of any race or ethnic group is good looking to every person of every racial or ethnic group. Needing computer assistance through Geek Squad I often deal with techs in the Phillipines, South America and India, all of different racial origins, and find that everyone of them finds our American jokes funny as we in America do. It is apparent that although we look different, in White, Black, Brown, Yellow and Red bodies, our brains are the same. In the past it was often thought that because of the advanced level of Northern European civilizations that other races and ethic groups were inferior cognitively. However, with the good nutrition and education of espeially America persons of these other ethnicities and races are now high level professionals such as professors and doctors. The origin of life on Earth is still a matter of speculation. Recent high level astrophysical research using radio telescopes has discovered that there can be no alien life forms capable of piloting any space travel vehicle transporting any extraterresrial ife forms, including humans to our planet. It is assumed that any advanced civilization can be detected through their use of radio waves. Howeve, no positive detection of such radio waves has been found. It may be that life on earth may be the only place life exists in the entire universe. 

T00.00375: Beyond Arrhenius: Fluctuation Theory for Dynamics Zeke A Piskulich Often the local temperaturedependence of dynamical timescales is evaluated by calculating activation energies using an Arrhenius approach to evaluate the numerical temperature derivative of the dynamical timescale. This numerical approach can fail however when the timescales are nonArrhenius, or when the system undergoes conformational or compositional changes with temperature. To circumvent these problems, we have developed a fluctuation theory approach for dynamics [Z.A. Piskulich, O.O. Mesele, and W.H. Thompson, “Activation Energies and Beyond,” J. Phys. Chem. A. 123, 7185 (2019).] that allows for derivatives of dynamical timescales to be evaluated from simulations at a single temperature. Presently, we use this fluctuation theory approach to calculate derivatives of the diffusion coefficient in liquid water under ambient conditions and demonstrate that they can be used to predict the temperaturedependence of the diffusion coefficient in the supercooled regime of water. We then demonstrate that fluctuation theory applied to water’s liquid structure can be used to calculate the enthalpy change associated with hydrogen bond exchanges, and that this quantity is closely linked to the activation energy. 

T00.00376: Reflection properties of uncoated and goldcoated InP photonic crystals HansPeter Wagner, ChiaWei Tu, Masoud Kaveh, Martin Fraenzl, Qian Gao, HarkHoe Tan, Chennupati Jagadish, Heidrun Schmitzer We investigated the spectral and angle resolved reflectance of uncoated and gold coated InP nanowire (NW) arrays which were grown by selective area epitaxy. The NW arrays were coated with a 12nm thick Al_{2}O_{3} film to suppress atmospheric oxidation. An additional 10nm thick gold film was further deposited around the NWs to investigate plasmonic effects. The arrays reveal pronounced FabryPerot oscillations due to their strong intrinsic birefringence, shifted for p and spolarized light. Goldcoating of the NW array increases the reflectance by a factor of two to three compared to the uncoated array. This increase is attributed to a plasmon resonance of the gold caps on top of the NWs and to a plasmonic antenna effect for ppolarized light. Both interpretations are supported by finitedifference timedomain simulations. The reflectance of light is highly polarizationdependent, making InP NW PhC arrays ideal micrometersized optical elements like polarizers, analyzers, and mirrors with potential applications in photonic integrated circuits. 

T00.00377: Compressibility of Ce at 200 GPa Christian V Storm, Earl F O'Bannon, Zsolt Jenei, James D McHardy, Simon G MacLeod, Evgeny Plekhanov, Malcolm I McMahon Cerium (Ce) is the most abundant of the rareearth metals and is of great interest to the highpressure community due to its unique behavior under pressure; it has a very complex phase diagram, including an isostructural volume collapse unique to the lanthanides and attributed to two minima in its interatomic potential. Above 13 GPa, Ce stabilizes in a bodycentered tetragonal (bct, tI2) phase. Using bevelled and toroidal DACs, we have statically compressed Ce up to 360 GPa and confirm the stability of this phase up to the highest pressures. We observe an increase in compressibility between 200250 GPa accompanied by a decline in the c/a ratio of the tI2 phase, indicating that the unit cell is becomes more cubic. The reason for these changes remains unexplored, but it is known that changes in the electronic structure, including charge localization or corelevel crossing can result in axial ratio anomalies and changes in the compressibility. We discuss the experimental data showing this shift and explore the possible causes. 
Withdrawn 
T00.00378: Gigahertz Topological Valley Hall Effect in Nanoelectromechanical Phononic Crystals. Postdoc Q Zhang realized topological valley Hall effect at 1 GHz in AlN membranes. Elastic waves are beautifully visualized by microwave microscopy. Lossless transmission through sharp corners and disorder. Qicheng Zhang Topological phononics offers numerous opportunities in manipulating elastic waves that can propagate in solids without being backscattered. Due to the lack of nanoscale imaging tools that aid the system design, however, acoustic topological metamaterials have been mostly demonstrated in macroscale systems operating at low (kilohertz to megahertz) frequencies. Here, we report the realization of gigahertz topological valley Hall effect in nanoelectromechanical AlN membranes. Propagation of elastic wave through phononic crystals is directly visualized by microwave microscopy with unprecedented sensitivity and spatial resolution. The valley Hall edge states, protected by band topology, are vividly seen in both real and momentumspace. The robust valleypolarized transport is evident from the wave transmission across local disorder and around sharp corners, as well as the power distribution into multiple edge channels. Our work paves the way to exploit topological physics in integrated acoustoelectronic systems for classical and quantum information processing in the microwave regime. 

T00.00379: Molecular Engineering of Network Solid Polymer Electrolytes for Enhanced Mechanical, Electrochemical and Ionic Transport Properties William R Fullerton Solid polymer electrolytes (SPEs) are regarded as a promising direction for the actualization of high energy density lithium metal batteries (LMBs). Currently, however, maintaining sufficient ionic conductivity, adequate electrochemical stability and optimum mechanical properties remains a significant challenge. In this work, we display how changes in molecular architecture and chemistry can tune such properties for optimal performance in LMBs. We synthesize and characterized a series of PEObased combchain crosslinked network SPEs (conSPE) that utilize a macromolecular crosslinker. Functionalized inorganic nanoparticles can also be introduced into the network serve as an additional crosslinking point and improve SPE modulus. The combchain molecular architecture design allows for the optimization of mechanical and transport properties through the widely tunable network mesh size. The chemical makeup of the polymer network is shown to play a crucial role in achieving high electrochemical stability and stable solid electrolyte interphase formation (SEI). The combination of stable SEI formation and high mechanical toughness of the conSPE enables excellent cycling performance at elevated current densities. The conSPE platform provides a promising route for future design of highperformance electrolytes for LMBs. 
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