Bulletin of the American Physical Society
2020 Fall Meeting of the APS Prairie Section
Volume 65, Number 22
Friday–Sunday, November 13–15, 2020; Virtual
Session B07: Parallel D |
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Chair: Jeff Terry, Illinois Institute of Technology |
Saturday, November 14, 2020 3:00PM - 3:15PM |
B07.00001: First Principles Design of A Heteroanionic Metal-Insulator Transition Compound Lauren Walters, Nathan Szymanski, Danilo Puggioni, James Rondinelli Using symmetry principles and electronic structure calculations we designed a novel metal-insulator transition (MIT) compound MoON [1]. We draw parallels between MoON and the well-studied VO$_{\mathrm{2}}$, demonstrating that properties such as the c/a lattice parameter ratio could be used for the design and identification of rutile MIT materials. The alpha and beta phase of MoON were identified from a set of prototype AB$_{\mathrm{2}}$ structures based upon energetics, band gap, and the c/a ratio. We show that the heteroanionic \textit{fac} ordering of the polyhedra are important for charge localization and singlet formation to open a band gap. Furthermore, our density functional calculations show how changes in the electronic band gap are driven by structural distortions, including 1D chain canting and dimer formation. Finally, we present design principles for the future prediction of metal-insulator transition materials. \textbf{Reference:} [1] N. Szymanski et al. Phys. Rev. Lett. \textbf{123}, 236402 (2019) \textbf{Funding Acknowledgement:} This work was supported by the National Science Foundation's (NSF) MRSEC program (DMR-1720139) at the Materials Research Center of Northwestern University. L. N.W. and J. M. R. were supported by NSF under DMR-1454688. [Preview Abstract] |
Saturday, November 14, 2020 3:15PM - 3:30PM |
B07.00002: Kinetic Monte Carlo Investigations of Metal-Oxide Atomic Layer Deposition David Magness, Bikash Timalsina, Emily Justus, David Magness \textsc{ATOMIC LAYER DEPOSITION (ALD) OF ULTRA-THIN METAL-OXIDES (SUCH AS ZNO OR AL2O3) AS THE CANDIDATE MATERIALS FOR ULTRA-THIN TUNNEL BARRIER LAYERS IS OF GREAT RESEARCH INTERESTS. IN THIS STUDY, WE ADOPT A 3D ON-LATTICE KINETIC MONTE CARLO (KMC) CODE DEVELOPED BY TIMO WECKMAN'S RESEARCH GROUP TO INVESTIGATE THE ROLE OF VARIOUS EXPERIMENTALLY RELEVANT FACTORS ON THE SIMULATED GROWTH OF ZNO LAYER. THE RESULTS FROM THE MODIFIED CODE INTENDED TO SIMULATE THE DEPOSITION OF AL2O3 ARE ALSO PRESENTED. ADJUSTABLE PARAMETERS INCLUDE CHAMBER PRESSURE AND TEMPERATURE, PULSE/PURGE TIMES, AS WELL AS THE STATE OF THE INITIAL SURFACE. THE ACCUMULATED DATA FROM THE CODE YIELDS INFO ON THE SIMULATED STRUCTURE, STOICHIOMETRY, MASS-GAIN, AND THE REACTION TYPES {\&} THEIR RESPECTIVE OCCURRENCE FREQUENCY. THE RESULTS ARE THEN COMPARED TO EXPERIMENTAL RESULTS FROM LITERATURE AND PREDICTIONS FROM AN AI TRAINED ON THE SIMULATED DATA. THE SUPPORT FROM NSF (EPMD DIVISION) AWARD NO. 1809284 IS GRATEFULLY ACKNOWLEDGED.} [Preview Abstract] |
Saturday, November 14, 2020 3:30PM - 3:45PM |
B07.00003: Study of Optical Absorption and Fluorescence of Pr$^{\mathrm{3+}}$ Doped Lead Boro-Germanate Glasses Suman Gautam, P. K. Babu, Saisudha Mallur Lead boro-germanate glasses doped with Pr $^{\mathrm{3+\thinspace }}$ions [x PbO-10 GeO$_{\mathrm{2}}$(90-x) B$_{\mathrm{2}}$O$_{\mathrm{3}}$0.5 Pr$_{\mathrm{2}}$O$_{\mathrm{3}}$, x $=$ 20, 30, 40, 50, 60 mol {\%}] are prepared by the conventional melt quenching technique. The glasses are studied using optical absorption, refractive index, and fluorescence measurements. The refractive index is measured using the Brewster's angle method. Optical absorption is recorded by a Varian CARY 5G UV-VIS spectrometer. From the absorption spectra, oscillator strengths, intensity parameters and radiative transition probabilities are calculated. The Pr$^{\mathrm{3+}}$ fluorescence spectrum is obtained by exciting the glass sample at 445 nm wavelength and examining the light emitted by the excited atoms with a LEOI-101 modular multifunctional grating spectrometer. Stimulated emission cross section ($\sigma_{\mathrm{P}})$ is one of the most important optical parameters and large values of that can improve the efficiency of energy conversion process in a photovoltaic cell operation We obtained the stimulated emission cross section for Pr$^{\mathrm{3+}}$ fluorescing transitions using the optical absorption parameters and fluorescence parameters. $\sigma _{\mathrm{P}}$ values are found to be large for these glasses and it shows compositional dependence [Preview Abstract] |
Saturday, November 14, 2020 3:45PM - 4:00PM |
B07.00004: Influence of metal and semiconducting nanoparticles on the optical properties of Dy}$^{\mathrm{\mathbf{3+}}}$\textbf{ ions in lead borate glasses. P K Babu, Saisudha Mallur The effect of glass composition and the influence of Ag, CdSe and ZnSe nanoparticles on the optical absorption and fluorescence of Dy-doped lead borate glasses are studied. Optical absorption and fluorescence spectra of Dy$^{\mathrm{3+}}$ ions show significant changes with glass composition, and the presence of semiconducting nanoparticles. We analyzed the hypersensitive transition, intensity parameters, radiative transition probability, stimulated emission cross section ($\sigma_{p})$, and the area ratio of the yellow to blue peak of Dy$^{\mathrm{3+}}$ ions. Fluorescence spectra of the glass containing CdSe nanoparticles show a well pronounced, characteristic broad emission. Deconvolution of these broad peaks yields average particle sizes that agree with the transmission electron microscope images. $\sigma_{p}$ shows significant increase for the glass containing CdSe nanoparticle of size 8-18 nm. Incorporating CdSe nanoparticles into lead borate glasses can produce significant electronic alterations to the local environment of Dy$^{\mathrm{3+}}$ ions to produce favorable enhancements to its optical properties. [Preview Abstract] |
Saturday, November 14, 2020 4:00PM - 4:15PM |
B07.00005: Discovery of promising, topological semimetal material SmMnBi2 Tiglet Besara, Sudha Krishnan Following the discovery of topological Weyl semimetals in non-magnetic materials, ferromagnetic Weyl semimetals have now been discovered with materials such as YbMnBi2, Co2MnGa, and Co3Sn2S2. With their different structures, this suggests that more ternary intermetallic compounds can be found displaying the connection between ferromagnetism and topology. We report on a growth and search for other isostructural ternary intermetallics, utilizing self-flux methods to grow single crystals, resulting in the promising candidate SmMnBi2. [Preview Abstract] |
Saturday, November 14, 2020 4:15PM - 4:30PM |
B07.00006: Designing TMDC-organic interfaces for effective charge transfer. Kushal Rijal, Fatimah Rudayni, Tika Ram Kafle, Wai-Lun Chan Excited-state electron transfer (ET) across molecules/transition metal dichalcogenide crystal (TMDC) interfaces is a critical process for the functioning of various organic/TMDC hybrid optoelectronic devices. Therefore, it is important to understand the fundamental factors that can facilitate or limit the ET rate. Here it is found that an undesirable combination of the interfacial band offset and the spatial dimensionality of the delocalized electron wave function can significantly slow down the ET process. Specifically, it is found that whereas the ET rate from TMDCs (MoS2 and WSe2) to fullerenes is relative insensitive to the band offset, the ET rate from TMDCs to perylene molecules can be reduced by an order of magnitude when the band offset is large. For the perylene crystal, the sensitivity of the ET rate on the band offset is explained by the 1D nature of the electronic wave function, which limits the availability of states with the appropriate energy to accept the electron. [Preview Abstract] |
Saturday, November 14, 2020 4:30PM - 4:45PM |
B07.00007: Polycaprolactone for Inorganic Materials Infiltration: A Promising Addition to Sequential Infiltration Synthesis Polymer Family Mahua Biswas, Joseph Libera, Seth Darling, Jeffrey Elam Infiltration of inorganic materials inside polymers is receiving a lot of attention for creating hybrid materials and patterned nanostructures. Sequential infiltration synthesis (SIS), derived from atomic layer deposition (ALD), involves gas phase reactions to infiltrate polymers with inorganic materials. The reactions between various polymer functional groups and inorganic precursors are unique, which makes it essential to understand the specific interactions for a range of precursors and polymers. In this work, in situ Fourier transform infrared spectroscopy (FTIR) measurements have been performed during Al$_{\mathrm{2}}$O$_{\mathrm{3}}$ and TiO$_{\mathrm{2}}$ SIS in three homopolymers: poly(methyl methacrylate) (PMMA), poly($\varepsilon $-caprolactone) (PCL), and poly(2-vinylpyridine) (P2VP). From the FTIR intensity, it is shown quantitatively that the interaction dynamics of these polymers with the metal precursors are substantially different. A key finding from this comparative study is that PCL interacts far more strongly with metal precursors compared to PMMA and P2VP. PCL may be an attractive polymeric template for inorganic infiltration processes, which has not been reported previously. [Preview Abstract] |
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