Bulletin of the American Physical Society
APS March Meeting 2023
Volume 68, Number 3
Las Vegas, Nevada (March 5-10)
Virtual (March 20-22); Time Zone: Pacific Time
Session Q32: New Directions for Growth |
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Sponsoring Units: DCMP Chair: Benazir Fazlioglu Yalcin, Pennsylvania State University Room: Room 224 |
Wednesday, March 8, 2023 3:00PM - 3:12PM |
Q32.00001: Formation of picosecond laser-induced periodic surface structures on Steel and Titanium for knee arthroplasty prosthetic Ali O Er, Salizhan Kylychbekov, Ali Oguz Er, Yaran Allamyradov, Inomjon Majidov, Zikrulloh Khuzhakulov, Justice ben Yosef, Chazz Kitchens Laser-induced periodic surface structures (LIPSS) have been studied extensively in recent decades due to their potential applications in various areas such as engineering, medical, optical, liquid transport and surface wetting, and friction and tribology. In this study, LIPSS is obtained on two prosthetic implants such as medical grade stainless steel and titanium in air and water using 1064 nm and 532 nm picosecond laser pulses. We obtained different surface morphologies depending on the environment and laser parameters. The surface morphology is analyzed by both Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM). The analysis of images shows that obtained periodic structures are in Low Special Frequency LIPSS (LSFL) with periodicity of around 600 nm and 1100 nm for lasers with wavelengths 532 nm and 1064 nm respectively in air. The periodicity increased when the experiment is carried out in water medium for both wavelengths. The morphology and periodicity of the LIPSS pattern were strongly dependent on the fluence. Ongoing experiments on biofilm formation and bacteria attachment on the patterned surface will also be presented. In addition, surface wettability by sessile drop method with water and diiodomethane as testing liquid will be presented. |
Wednesday, March 8, 2023 3:12PM - 3:24PM |
Q32.00002: Bulk incorporation studies of Sn atoms into Si-MOS substrates for use as a nuclear spin qubit Troy A Hutchins-Delgado, Deanna M Campbell, Tzu-Ming Lu, David A Lidsky, Chris Smyth, Christopher R Allemang, Paul G Kotula, Dwight R Luhman Recent theoretical work suggests that Sn atoms incorporated into silicon are compelling candidates for nuclear spin qubits in a quantum dot shuttle-based architecture [1]. To realize this vision, a sparse density of Sn atoms will need to be reliably incorporated into silicon in the region where the quantum dots are formed. We will present the results of bulk incorporation studies of implanted Sn into Si-MOS material stacks. Using a combination of different characterization techniques, we find ample evidence that implanted Sn does incorporate in silicon near the oxide interface where an electron confined by a quantum dot would reside in a qubit device. In addition, we will discuss progress on the development of our Si-MOS quantum dot platform and implications for implanting Sn into silicon quantum dots. |
Wednesday, March 8, 2023 3:24PM - 3:36PM |
Q32.00003: Capturing architected liquid bridge shapes via controlled stretching Ji Hoon Kim, Jaekyoung Kim, Sohyun Kim, Hyunsik Yoon, Won Bo Lee Liquid-mediated patterning, which is a manufacturing method exploiting the nature of liquids, has achieved great advances in micro- and nano-fabrication techniques. The easily deformable nature of liquids enables fully confined liquid morphing (also known as template-based method), and the surface tension of the liquid allows for a lot of variations of droplet microfluidics. A liquid bridge, which is formed when a droplet of liquid meets two solid surfaces, exhibits the characteristics of both; therefore, it can unfold a new route for microfabrication and related applications. In this study, liquid bridge-shaped microstructures on a target substrate and template are demonstrated. Through the synergy of theoretical investigations and construction with elastomeric spacers, the geometry of liquid bridges can be modeled as a function of the solid and liquid properties, separation distance, and morphology of solid surfaces. This research provides numerous derivatives of structures with tunable sizes, morphologies, and compositions. In particular, the convex (with negative gaussian curvature) morphology of the liquid bridge-shaped microstructures exhibits liquid-repellent characteristics; therefore, it can be exploited for isotropic and anisotropic wettability manipulation. The advances in this study related to semi-confined patterning toward scale-down and controllability enable expanded variations for microfabrication, surface engineering, and liquid manipulation. |
Wednesday, March 8, 2023 3:36PM - 3:48PM |
Q32.00004: Formation of wrinkled film layer between symmetrically stretched substrates Jeongrak Lee, Hyunsu kwak, Hanseong Jo, Anna Lee Due to the recent pursuit of human-friendly form factors for mobile devices and the advancement of IoT technology, the need for highly stretchable electrodes is on a rapid rise. Here we propose a new type of stretchable circuit containing a wrinkled electrode layer between symmetrical stretched substrates. Unlike the bilayer structure, where warpage easily occurs, the symmetric tri-layer maintains its structural stability in higher elongation. Thus, high encapsulation density can be achieved by minimizing the thickness of the substrates without requiring thick foundation layers to avoid warpage. The wrinkled layer is fabricated by sandwiching a thin conductive polymer between two substrates pre-stretched to the same elongation followed by releasing. The thin film layer is wrinkled due to compressive stress during the releasing process. Symmetry reduces global mechanical instabilities such as bending and curling even at an extreme elongation of 300% or more and produces a predictable sinusoidal wrinkle without folding. Using high-performance stretchable electrodes containing Ag-nanowires or graphene has the potential for applications in displays, soft robotics, and ergonomic devices. |
Wednesday, March 8, 2023 3:48PM - 4:00PM |
Q32.00005: Mitigating Cracks on Mesomorphic Ceramic Films Prepared by Blade-Coatin Xinquan Cheng, Wenshi Zhang, Shaw H Chen, Mitchell Anthamatten Mesomorphic ceramics, defined as inorganics with static liquid crystalline superstructures, can serve as waveplates, achieving cost-efficient polarization control. The optical retardance of a waveplate requires a sufficient thickness. However, crack formation upon thermal treatment of mesomorphic ceramics degrades both optical and mechanical properties. To mitigate crack formation, we fabricate 2-µm-thick mesomorphic ceramic films of ZnO using three different blade-coating methods: treatment of blade-coated films with ZnO precursors, subsequent blade coating of multiple thin layers of nanorods to fill cracks, and a hybrid approach involving multiple layers and precursor treatment. Using the hybrid approach, a 2-µm-thick MC film with a birefringence of 0.088 and a transparency of 82% at 1065 nm was achieved. This reported method to mitigate cracks in sintered mesomorphic ceramics takes a critical step toward crack-free, wide-area, inorganic waveplates. Crack-free mesomorphic ceramic films could benefit diverse applications including thin-film transistors, optoelectronics, and photocatalysis. |
Wednesday, March 8, 2023 4:00PM - 4:12PM |
Q32.00006: Atomic restructuring of ion beam sputtered TiO2 : GeO2 thin films with annealing Ruth Osovsky, Emmett Randel, Aaron Davenport, Samuel Castro Lucas, Michael Van Erdewyk, Justin B Sambur, CARMEN S MENONI Amorphous oxides thin films are extensively used in optical interference coatings, and as dielectric barrier films. Tunable properties accessible through the ion beam sputtered (IBS) codeposition of two or more cations in reactive oxygen atmospheres enables the synthesis of amorphous oxides mixtures with tailored optical and mechanical properties. This work reports on the study of the evolution of the atomic structure and bonding of an IBS mixture of 44% TiO2 and 56% GeO2 with annealing through Raman and Infrared spectroscopies. Characteristic vibrational signatures of a-GeO2 are altered in the mixture, indicating that the Ti ions are introduced into the lattice of a-GeO2 in substitutional mode, as evidenced by a higher distribution in the inter-tetrahedral Ge-O-Ge angles due to longer and weaker Ti-O bonds, and suggesting a more open and flexible network. Annealing causes structural reorganization on the TiO2 : GeO2 mixtures, as observed by the evolution in the Ge-O-X (X=Ge, Ti) vibrational signatures, more significantly at temperatures ≥ 500°C. This work brings out a new understanding of the modifications in the atomic structure of TiO2 : GeO2 mixtures upon thermal treatment, which is critical to understand the mechanisms involved in affecting internal friction of this promising high refractive index material for coatings of gravitational wave detectors [1]. |
Wednesday, March 8, 2023 4:12PM - 4:24PM |
Q32.00007: Kinetic Monte Carlo Simulations of Quantum Dot Self-Assembly Christian Ratsch, Matthew Abramson, Hunter J Coleman, Ryn Olyphant, Paul J Simmonds, Tim P Schulze For many heteroepitaxial systems growth proceeds in the Stranski-Krastanov (SK) growth mode, where layer-by-layer growth is followed by the formation and growth of three-dimensional (3D) islands. These resulting 3D islands are often referred to as quantum dots (QDs). In this talk, we present detailed and systematic kinetic Monte Carlo (KMC) simulations to study the effects of key model parameters including strain, growth temperature, and deposition rate. We show that increasing the strain lowers the apparent critical thickness of the wetting layer that is defined by the onset of QD formation. Similarly, increasing the growth temperature lowers the apparent critical thickness, until intermixing, and the resulting relevance of entropic contributions, becomes more significant. Recent experiments for Ge QDs grown on InAlAs(111) show a transition from SK growth to Volmer-Weber (VW) growth (where QDs form before the formation of even a single wetting layer) as the substrate temperature increases. We use our KMC simulations to explain this unexpected behavior. |
Wednesday, March 8, 2023 4:24PM - 4:36PM |
Q32.00008: Role of oxygen vacancies in the surface charging of CoFe2O4 thin films: A temperature dependent X-ray photoemission spectroscopy study of CoFe2O4 thin films Arjun Subedi, Detian Yang, Xiaoshan Xu, Peter A Dowben We observed large increases in the measured binding energies of the Co and Fe 2p3/2 levels in X-ray photoemission spectroscopy (XPS) of CoFe2O4 thin films at room temperature, due to large photovoltaic surface charging of the film. When the film was heated to 332 0C from room temperature, the binding energies of the 2p3/2 core levels of Co and Fe atoms decreased significantly by about 5 eV. The binding energies of Co and Fe 2p3/2 levels, however, did not change when the film was cooled in vacuo from 332 0C to room temperature. This irreversible transition became reversible when the CoFe2O4 was annealed in oxygen. The results are significant in that surface charging and hence the surface electronic properties can change with number of oxygen vacancies. We can compare the surface charging seen with CoFe2O4 to NiFe2O4 and NiCo2O4 thin films. The increasing conductivity (or decreasing surface charging) at the surface with increasing temperature may be due to increased carrier concentration, but the nature of the surface oxide and the surface defect density may play a role. |
Wednesday, March 8, 2023 4:36PM - 4:48PM |
Q32.00009: Spin Interactions of On-surface Grown Metal Organic Structures Studied Using Scanning Tunneling Microscopy Se-Jong Kahng, Yerin Lee, Min Jeong Kang, Min Hui Chang On-surface synthesis attracts much attention because it provides a facile way to prepare various molecular structures such as graphene nano-ribbons, chiral supramolecular networks, and metal-organic structures in ultrahigh vacuum. The metal organic molecular structures often have spin-spin interactions that can be used for molecular spintronics and quantum information science, but were rarely probed at the atomic level. Here, we report on the atomic, electronic, and spin structures of metal-organic structures of 2,3,6,7,10,11-Hexahydroxytriphenylene (HHTP) and Ni studied using scanning tunneling microscopy (STM). The metal-organic structures were prepared by on-surface synthesis on Au(111) and showed several different structures that can be explained by O – Ni – O bonds. Strong zero bias peaks were observed implying spin-spin interactions between d-orbitals of Ni and conduction electrons of surfaces. Our study shows that on-surface grown metal-organic structures provide excellent platform for studying spin-spin interactions. |
Wednesday, March 8, 2023 4:48PM - 5:00PM |
Q32.00010: Kinetic roughening of the color phase boundaries in ionic conducting oxide thin films Heung-Sik Park Ionic migration in oxides is a basic mechanism for the operation of various devices, such as solid oxide fuel cells and resistive switching memories. Here, we explore Bi0.7Ca0.3FeO3-δ thin films, which show ionic conduction and electrochromism [1], to study kinetic roughening of the boundaries between oxygen-vacancy-poor phase (δ = 0) and stoichiometric phase (δ = 0.15) [2,3]. Each of the phases can be spatially separated by electric fields and distinguished by color contrast through optical microscope. The width of the boundaries between two phases varies depending on applied voltage. Roughness exponents(ζ) of the boundaries saturate to ζ = 1. The dynamic motion of ionic phase boundaries is described based on the universal kinetic roughening theory. |
Wednesday, March 8, 2023 5:00PM - 5:12PM Author not Attending |
Q32.00011: Fundamental properties of hydrogen-functionalized GaSe monolayer Duyen T Huynh Functionalization reveals potential opportunities for modifying essential properties and designing materials due to the strong interaction between functionalized atoms and the surface. Among them, hydrogenation possesses such a way to control electronic and optical characteristics. In this paper, the stability and transformed electronic, optical properties of H-functionalized GaSe in two cases (single and double sites) were reported that exhibit the effects of hydrogen functionalization via first-principles calculations. Formation energies suggest that H-functionalized Gase systems are stable for construction. H-GaSe and 2H-GaSe display distinct properties based on the functionalized way (single or double-site functionalization). Accordingly, H-GaSe is metallic, while 2H-GaSe belongs to a semiconductor. The magnetic configuration with ferro- and anti-ferromagnetic could be found in H- and 2H-functionalized cases through spin distribution, respectively. Especially, the chemical hybridized bonds of Se-H, Ga-Se, and Ga-Ga corresponding to s-sp3 and sp3-sp3 bondings, respectively, are clearly verified in the orbital-projected density of states and charge density. The optical properties of 2H-GaSe could provide the main characteristics of a semiconductor, which is the limited range of transparency by electronic absorption at short and long wavelengths. Moreover, increasing the number of the segment GaSe (L) could change bandgap leading to application in the bandgap engineering of the 2H-GaSe systems. Thus, hydrogen functionalization could provide the possible manner for adjusting and controlling features of GaSe, promising for the development of electronic devices and applications. |
Wednesday, March 8, 2023 5:12PM - 5:24PM |
Q32.00012: Solid state reduction of nickelate thin films Wenzheng Wei, Kidae Shin, Hawoong Hong, Yeongjae Shin, Frederick J Walker, Charles H Ahn The doped square-planar nickelates are a novel class of metal oxide superconductor. Their synthesis involves growth of a perovskite precursor followed by topotactic reduction. Current reduction processes involve annealing in vacuum with CaH2 powder. This ex-situ process allows control of the oxygen vacancy content in the thin films but is not easily amenable to in-situ measurements of the dynamics of square-planar nickelate formation. |
Wednesday, March 8, 2023 5:24PM - 5:36PM |
Q32.00013: Epitaxially Controllable h-BN on Graphene Sheng Shong Wong The only insulation material in 2-D family, hexagonal boron nitride (h-BN), has been widely used as substrates in the field of 2-D electronic device. The atomically flat and inert surface provides a low scattering probability environment for electrical and quantum transport. In recent years, there are more and more studies of h-BN as main character involving quantum optics and twistronics. Here, we developed a layer-controlled growth method of h-BN on graphene/4H-SiC substrate by plasma-assisted molecular beam epitaxy (PA-MBE). The angle-resolved photoemission spectroscopy (ARPES) spectrum discovers the h-BN π band splitting at K point in experiment first time, revealing the stacking sequence of our h-BN is AB rather than AA' stacking. In addition, according to crystallographic point group theory, AB stacking is symmetry breaking, which results in the non-zero polarization in bilayer h-BN system. The piezoresponse force microscopy (PFM) measurement not only indicating the existence of polarization, but also demonstrating the capability of switching polarization up or down in bilayer h-BN system, i.e. ferroelectric. These fundamental investigations display an enormous potential for bilayer h-BN system as a candidate for ferroelectric non-volatile random-access memory (FRAM) in 2-D electronics. |
Wednesday, March 8, 2023 5:36PM - 5:48PM |
Q32.00014: Conductance enhancement at non-polar SrHfO3/BaSnO3 interface Jongkyoung Ko, Kookrin Char, Oliver Bierwagen We report two-dimensional electron gas-like (2DEG) characteristics at the non-polar SrHfO3(SHO)/BaSnO3(BSO) interface. SHO/La-doped BSO (BLSO) interfaces are grown on MgO (100) substrates with BaSnO3 and BaHfO3 buffer by pulsed laser deposition. The epitaxial growth of SHO/BLSO interface structure was confirmed by high resolution X-ray diffraction and reciprocal space mapping. We have measured the electrical properties of the SHO/BLSO interface as a function of the La doping ratio of the BLSO layer as well as the thickness of the SHO layer. Additionally the carrier confinements of SHO/BLSO interfaces were measured by Capacitance-Voltage profiling technique with a mercury probe. The 2DEG-like behavior will be discussed first in terms of potential oxygen vacancy formation at the interface due to very slow oxygen diffusion in SHO. We will also discuss the possibility for the large conduction band offset at the interface between SHO and BSO to create the potential well at the interface. |
Wednesday, March 8, 2023 5:48PM - 6:00PM |
Q32.00015: Controlling thermal transport and dewetting in nanoscale molten metal films Linda J Cummings, Ryan H Allaire, Lou Kondic Pulsed-Laser induced Dewetting (PLiD) is a simple technique that may be used to create metallic nanoparticles. A nanoscale metal film is plated on a Si or SiO2 substrate, and a pulsed laser is applied to melt the film, which then dewets and breaks up into nanoscale metal droplets. On removal of the laser pulse, the droplets resolidify as metallic nanoparticles. We model a setup in which the metal film is "patterned" onto the substrate, leaving certain areas free of metal. Though the substrate is optically transparent and does not absorb laser heat, it can absorb heat from the overlying metal, which is then transmitted laterally. Such lateral heat transport in the substrate can influence how melting and dewetting occurs in the overlying metal film, and ultimately how and where nanoparticle formation occurs. We present an asymptotically simplified model for the heat transport and fluid dynamics of the system, and proof-of-principle numerical simulations (implemented on a GPU) demonstrating how simple metal patterns may be used to control the final nanoparticle formation. |
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