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 S28: Computational Design, Understanding and Discovery of Novel Materials VIIFocus
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Sponsoring Units: DMP Chair: Jorge Munoz, University of Texas at El Paso; Cormac Toher, University of Texas at Dallas Room: Room 220 |
Thursday, March 9, 2023 8:00AM - 8:36AM |
S28.00001: Predicting defects and doping of semiconductors - progress toward high-throughput calculations and relevance to materials discovery Invited Speaker: Vladan Stevanovic To be useful semiconductors need to be doped. The ability to be doped (or dopability) is a phenomenon that goes beyond the dissolution of aliovalent elements as the introduced charge carriers may reside in localized (deep) defect states or could be compensated by the intrinsic point defects. As a consequence, many material systems exhibiting finite electronic band gaps are not dopable at all or allow only one charge carrier type. Hence, predicting dopability and the existence of effective dopants needs to be an integral part of any functional (semiconductor) materials discovery effort. While modern defect theory and defect calculations allow for relatively accurate assessment of the intrinsic defect chemistry, doping limits and effective dopants, the calculations themselves are demanding, requiring significant human time and computational resources, and are hence, challenging to perform in a high-throughput fashion. In this talk I will review and discuss our efforts in automating defect calculations with goal of making them an integral part of the high-throughput materials discovery workflows. Our pylada python environment together with the pylada-defects module offers automatic generation of defects structures, automated job scheduling and control, as well as post-processing of the results including application of the finite size corrections and calculations of the defect formation energies. I will also present our recent searches for wide gap semiconductors for power applications and semiconductor-impurity qubits where defect calculations and dopability (and doping) assessment are of utmost importance. |
Thursday, March 9, 2023 8:36AM - 8:48AM |
S28.00002: Structural characterization of boron-doped alumina for smart lubricants Nicholas J Wilson, Todd Lombardi, Ashish K Kasar, William Wolfs, Pradeep L Menezes, Eunja Kim We have investigated material properties of ceramic alumina (Al2O3) doped with boron oxide (B2O3) using density functional theory (DFT). Alumina exhibits favorable physical properties, including a high melting point, hardness, and corrosion resistance. This material can also possess good tribological properties i.e., friction, lubrication, and heat transfer, which are enhanced with the addition of solid lubricants such as boron oxide. In this study we have carried out atomic modeling of alumina and the stable aluminum borate phase. Our models revealed that the commonly accepted 9Al2O3 2B2O3 polymorph contains ten aluminum oxide molecules within its structure. Defect formation energy calculations for several possible scenarios revealed that it is very energetically unfavorable to create vacancies in the 10Al2O3 2B2O3 cell, and theoretically simulated x-ray diffraction patterns of the optimized 10Al2O3 2B2O3 cell match well with experimental results. Through phonon analysis of both alumina and aluminum borate we produced theoretical infrared spectra for comparison to experimentally obtained spectra. The phonon calculations carried out can also be used to analyze tribological properties based on active modes. |
Thursday, March 9, 2023 8:48AM - 9:00AM |
S28.00003: Theoretical investigation of growth mode for oxidation resistance copper film Bipin Lamichhane Copper is a critical material for quantum electronics, semiconductor industry, and modern electronics, but oxidation and corrosion limit its application. First-principles total-energy calculations based on density functional theory is used to investigate the diffusion of single and clusters of copper atoms in alumina. The exchange-correlation energy is described by the generalized gradient approximation (GGA) of Perdew–Burke–Ernzerhof (PBE) and projected augmented wave (PAW) method is employed. Our calculation of diffusion of single copper and clusters of copper atoms on an Al-terminated surface agrees with the experimentally observed new growth mechanism for the preparation of metal films with atomically flat surfaces. Moreover, atomically flat Cu(111) without multi-atomic step edge is oxidation resistant |
Thursday, March 9, 2023 9:00AM - 9:12AM |
S28.00004: Examining the Ethane Selective Potential of MOFs for Ethylene Purification Wells W Graham, Jing Li, Feng Xie, Timo Thonhauser Ethylene plays an important role in the petrochemical industry, however cryogenic separation—the most popular method for purifying ethylene—is also one of the most expensive and energy intensive processes in the chemical industry. Therefore, alternative cost-effective technologies to efficiently purify ethylene at ambient conditions are of paramount interest. Highly porous metal organic frameworks (MOFs) have emerged as promising materials for the task of gas separation due to their highly tunable nature. However, one major issue is their ethylene-selective separation which leads to the need for a desorption process to obtain the desired ethylene. Consequently, ethane selective MOFs are of significant interest due to potential savings of time and energy. Here we combine ab initio calculations with dynamic sorption experiments to examine the effectiveness of pore geometry tuning in synthesizing ethane selective MOFs. The main focus of the study is on MOF-801 with UiO-66 being used for comparison as it selects for ethane and shares the same metal cluster structure. MOF-801 shows a noticeable enhancement in selectivity of ethane when compared to UiO-66 due to the different pore geometry. This improved selectivity leads to polymer grade ethylene of over 99.9% purity. The experiments also show that MOF-801 is quite robust as it maintains its stability in the presence of various solutions, and that the MOF also has strong structural integrity giving it great recyclability. |
Thursday, March 9, 2023 9:12AM - 9:24AM |
S28.00005: Modeling electronic coupling between Heme groups in extracellular cytochrome polymers with first-principles density functional theory Luke Nambi Mohanam, Yuanming Song, Rafael Umeda, Khawla Mustafa, Douglas J Tobias, Allon I Hochbaum, Ruqian Wu, Sahar Sharifzadeh OmcS is an example of a micro-meter extracellular cytochrome peptide wire that transfers electrons; vital to the metabolism of Geobacter sulfurreducens, the bacteria that excretes it. Cryo-EM experiments (PDB: 6ef8) show a single peptide monomer with 6 heme groups stacking to form the polymer wire, creating a linear chain of heme groups. For OmcS and other similar peptide wires, these heme groups are identified in the literature as the charge carrier sites for an excess electron under aerobic conditions; orthogonalized heme charge carrier sites are used for modeling charge carrier evolution. To better understand the charge carrier dynamics in these peptide wires, we present canonical Kohn-Sham orbitals of isolated single and double heme group subsystems from the OmcS structure, manipulating the inter-heme geometry in order to tune the extracted charge carrier site energies and couplings. DFT simulations thus show the relationship between charge carrier binding energy, coupling, and dimer structure. Our results indicate that modifying the inter-heme geometry can result in desired charge carrier properties. |
Thursday, March 9, 2023 9:24AM - 9:36AM Author not Attending |
S28.00006: Metavalent Bonding Origins of Unusual Properties of Group IV Chacogenides Raagya Arora, Umesh V Waghmare, C. N. R. Rao A distinct type of metavalent bonding (MVB) was recently proposed to explain unusual set of anomalous functional properties of group IV chalcogenide crystals. However, electronic mechanisms of MVB and emergent properties are yet to be understood. Through theoretical analysis of evolution of MVB along continuous paths in structural and chemical composition space, we show that MVB arises in rocksalt chalcogenides stabilized as weakly broken symmetry states of the parent metal of simple cubic crystal of Group V metalloid. Symmetry-breaking structural and chemical polar fields couple with its degenerate frontier states opening up a gap resulting in MVB state with high polarizability and sensitivity to bond-lengths. It transforms discontinuously to covalent and ionic semiconducting states with stronger symmetry breaking structural and chemical fields respectively. Wannier function analysis reveals mixed, long-range bonding and antibonding pp, sp orbital interactions, supporting high coordination numbers. MVB involves bonding and antibonding pairwise interactions alternating along linear chains of at least five atoms, which facilitate long range electron transfer in response to polar fields causing unusual properties. Our precise picture of MVB predicts anomalous second order Raman scattering as an addition to set of their unusual finger-printing properties, and will guide in design of new metavalent materials with improved thermoelectric, ferroelectric and nontrivial electronic topological properties. |
Thursday, March 9, 2023 9:36AM - 9:48AM |
S28.00007: Coherent Ising machine for the reverse design of composite material Juan Han We derive the effective dielectric function of composite material by using effective medium theory based on the Maxwell-Dirac correspondence. We relate the polarizability of the inclusion particle to the extinction cross-section solved by the Mie scattering theory. The effective dielectric function we obtained is determined by five parameters: ? (wavelength of light), r (radius of inclusion particle), ? (fill fraction), ?_h (permitivitty of host medium) and ?_i (permitivitty of inclusion medium). By optimizing the above parameters and the thickness of the composite material, we can get reflection, transmission and absorption spectra closely to the target spectra. We propose to run the combinatorial optimization process on a coherent Ising machine. The combinatorial optimization problem is connected to the ground state of Ising model through QUBO (Quadratic Unconstrained Binary Optimization). The reverse design method is useful to discover optimal nanocomposite thin films with desired broadband spectral properties. |
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