Bulletin of the American Physical Society
APS March Meeting 2020
Volume 65, Number 1
Monday–Friday, March 2–6, 2020; Denver, Colorado
Session U43: Computational design and discovery of novel materials V: Electronic structureFocus
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Sponsoring Units: DCOMP DMP Chair: Vincent Crespi, Pennsylvania State University Room: 702 |
Thursday, March 5, 2020 2:30PM - 3:06PM |
U43.00001: Towards ideal topological materials: Comprehensive database searches using symmetry indicators Invited Speaker: Xiangang Wan Although the richness of spatial symmetries has led to a rapidly expanding inventory of possible topological crystalline (TC) phases of electrons, physical realizations have been slow to materialize due to the practical difficulty to ascertaining band topology in realistic calculations. Here, we integrate the recently established theory of symmetry indicators of band topology into first-principle band-structure calculations and apply it to all non-magnetic compounds in the 230 space groups. An exhaustive database search reveals thousands of TM candidates. Of these, we highlight the excellent TMs, the 258 topological insulators and 165 topological crystalline insulators which have either noticeable full band gap or a considerable direct gap together with small trivial Fermi pockets. We also give a list of 489 topological semimetals with the band crossing points located near the Fermi level. All predictions obtained through standard generalized gradient approximation (GGA) calculations were cross-checked with the modified Becke-Johnson (MBJ) potential calculations, appropriate for narrow gap materials. With the electronic and optical behavior around the Fermi level dominated by the topologically non-trivial bands, these newly found TMs candidates open wide possibilities for realizing the promise of TMs in next-generation electronic devices. |
Thursday, March 5, 2020 3:06PM - 3:18PM |
U43.00002: First principle study of structural, electronic and magnetic properties of layer-structured MnSb Bipin Lamichhane, Dinesh Thapa, Chandani Nandadasa, Junseong Song, Sung Wng Kim, Seong-Gon Kim Manganese antimonide (MnSb) as a half-metallic ferromagnets can be used as a spin injector in semiconductor to develop spintronic devices. We performed ab initio total-energy calculations and geometry optimizations within Density Functional Theory (DFT) using the generalized gradient approximation (GGA) Perdew–Burke–Ernzerhof (PBE) functional and the projected augmented wave (PAW) method to investigate the structural, electronic, and bonding properties of layer-structured MnSb. We found a metallic density of states (DOS) in one spin channel (majority spin) and a band energy gap at the Fermi level in another (minority spin), which presents MnSb to have a half metallic character. Furthermore, atom projected band structure was used to investigate the electronic contributions from Mn and Sb atoms |
Thursday, March 5, 2020 3:18PM - 3:30PM |
U43.00003: Near-Fermi-level electronic states in hexagonal ABC compounds from first principles Konrad Genser, Karin M Rabe Ternary ABC intermetallic compounds exhibit a rich variety of crystal structures and electronic properties. In this work, we study the band structures of real and hypothetical ABC intermetallic phases with structures obtained by stacking binary honeycomb layers with single layers of interstitial atoms in various ways, using first principles calculations to determine the structural parameters and the bands in each phase. We use this dataset to analyze and model the bands near the Fermi level to classify the systems considered and to extract a set of rules that allows us to to predict and design hexagonal ABC intermetallic materials with targeted transport and optical properties, connecting to experimental measurements on known hexagonal ABC phases. |
Thursday, March 5, 2020 3:30PM - 3:42PM |
U43.00004: A symmetry-based approach to reciprocal space path selection in band structure calculations Jason Munro, Katherine Latimer, Shyam Dwaraknath, Kristin Persson The calculation of band structures is a critical step in describing many different properties of crystalline solids such as optical absorption, and both thermal and electronic transport. Most commonly, these are computed along a one-dimensional path in reciprocal space, which is presumed to capture important features of the entire dispersion landscape. However, conventions for choosing this path rely on data for high-symmetry points and lines in the first Brillouin zone, defined using different arbitrary criteria and an inflexible predefined unit cell. Furthermore, this data is contained in hard-coded lookup tables for different crystal classes and lattice vector lengths. To address these issues, a new “on-the-fly” symmetry based algorithm and utility for obtaining paths in reciprocal space is presented. For an arbitrary input cell, the site-symmetries of points and lines in the first Brillouin zone are determined and used to define the high-symmetry criteria. A smooth path connecting them is then obtained using graph theory based tools. This new framework not only allows for increased flexibility, but is also shown for a general high-symmetry criteria to provide new notable features in the electronic band structure for systems with both magnetic and nonmagnetic symmetry. |
Thursday, March 5, 2020 3:42PM - 3:54PM |
U43.00005: Electronic structure of bulk SmSbTe Brandon Miller, Jin Hu, Salvador Barraza-Lopez
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Thursday, March 5, 2020 3:54PM - 4:06PM |
U43.00006: Atomic-Level Insight into Oxygen Adsorption on (hkl) Platinum Surfaces and Implications for the Reactivity in the Oxygen Reduction Reaction Shiyi Wang, Enbo Zhu, Yu Huang, Hendrik Heinz Understanding of the oxygen reduction reaction (ORR) on nanometal catalysts and specific rate predictions remain a major challenge. We quantified adsorption of molecular oxygen on Pt (100), (111), and (110) surfaces in common electrolytes and for a range of applied potentials in several times higher accuracy than feasible before using molecular dynamics simulations, and explore the following colvalent bond formation using density functional theory calculations. A direct correlation between the oxygen affinity to Pt (hkl) surfaces and the experimentally measured ORR activity in the order Pt(100) < Pt(111) < Pt(110) in HClO4 solution and Pt(111) < Pt(100) < Pt(110) in H2SO4 and H3PO4 solutions is discovered. The adsorption energies are in a range to explain specific rate differences. Experimental data for the time scale of events support that the ORR activity is driven by O2 adsorption and initial chemisorption. The methods can be potentially applied to metal and alloy surfaces of any regularity, shape, and composition to provide quantitative insights into metal-electrolyte-gas interfaces, and promote the rational design of more effective catalysts for ORR, OER, and other electrode reactions to the large nanometer scale. |
Thursday, March 5, 2020 4:06PM - 4:18PM |
U43.00007: Novel fundamental bounds in photovoltaic materials Ella Banyas, Liang Tan Effective photovoltaic materials require not only an ideal band gap, but a high carrier mobility. Identifying new candidate photovoltaics can be challenging, as generalized methods for predicting materials with the requisite properties do not yet exist. Here we use a local orbital-based approach and the nearsightedness principle to derive novel analytic bounds on effective masses, which are inversely proportional to carrier mobility in the Boltzmann transport limit. These bounds explicitly depend on both the electronic band structure (e.g. the band gap) and the physical structure of the crystalline material itself, thereby enhancing our ability to identify materials classes that have both small band gaps and high mobilities. We present the methodology used for generating these “structure-informed” fundamental bounds and compare current results to a high-throughput survey of Materials Project data. |
Thursday, March 5, 2020 4:18PM - 4:30PM |
U43.00008: Catalytic properties of one-dimensional electrides: A first-principles study Jinseon Park, Mina Yoon Electrides are ionic compounds in which “free” electrons (anionic electrons) are confined in a low-dimensional cavity space. The characteristic features of electrides—the existence of large void spaces and non–nucleus-bound anionic electrons—make them attractive for various applications, such as gas storage, electron/ion transport, and electrocatalytic processes. Recently, we identified Cs3O as a new type of one-dimensional (1D) electride with nontrivial band topology. The compound Y5Si3 also was recently discovered, another 1D electride that exhibits excellent durability and catalytic efficiency. We demonstrate that hexagonal Y5X3 (X = Ge, Sn, and Pb) also can be classified as a 1D electride with different lattice parameters. A global structure search confirms that these compounds are thermodynamically stable. To understand the catalytic properties of Y5X3 as a reducing agent, the interaction between a Y3X3(001) surface and a Cu adsorbate is investigated, and the ability of the Y5X3 to donate electrons to Cu is quantitatively analyzed in terms of charge transfer. We further shed light on the role of anionic electrons in the electrochemical corrosion of Cu atoms. Our results are expected to provide a better understanding of catalytic properties of 1D electrides. |
Thursday, March 5, 2020 4:30PM - 4:42PM |
U43.00009: Predicting 2D Materials with Machine Learning Gabriel Schleder, Carlos Mera, Adalberto Fazzio The increasing interest and research on two-dimensional materials has not yet translated into a reality of diverse materials applications. To go beyond graphene and transition metal dichalcogenides for several applications, candidates with desirable properties must be proposed. We use machine learning techniques to identify thermodynamically stable 2D materials, which is the first essential requirement for any application. |
Thursday, March 5, 2020 4:42PM - 4:54PM |
U43.00010: Predicting band alignments and structural interdependence in 2D hybrid organic inorganic halide lead perovskites from First-Principles Calculations Sampreeti Bhattacharya, Yosuke Kanai Authors: Sampreeti Bhattacharya, Yosuke Kanai |
Thursday, March 5, 2020 4:54PM - 5:06PM |
U43.00011: A tunable and unidirectional one-dimensional electronic system Nb2n+1SinTe4n+2 Zhen Zhu, Hao Zheng, Jinfeng Jia One dimensional (1D) electronic system is a versatile platform hosting novel physics, such as charge density wave, Su-Schrieffer-Heeger (SSH) topological state and solitons, Tomonaga-Luttinger Liquid etc. However, since real 1D materials do not exist in nature, quasi-1D structures in 3D crystals become a practical substitute. Here, we systemically study the surface electronic properties on layered composition-tunable compounds Nb2n+1SinTe4n+2 (n=1~5), which is predicted to be a nodal-line semimetal when n=1 (Nb3SiTe6). Via scanning tunneling microscopy/spectroscopy, we observe 1D chains spontaneous formed on the surface of the compounds. We uncover that with the increasing of n, the distance between the chains becomes larger, and the 1D electronic state is developed in the compounds with n ≥ 3. Our first-principle calculations reveal that the nodal-line in Nb3SiTe6 and the 1D electronic state in the crystals with higher n in fact arise from the same bands, which are protected by the same nonsymmorphic symmetry. Furthermore, we can understand the evolution of the electronic states based on a simple SSH type picture. Our experiment demonstrates the first tunable 1D electronic system, which offers a concrete platform for the exploration of intriguing 1D electron physics. |
Thursday, March 5, 2020 5:06PM - 5:18PM |
U43.00012: An ab-initio study of structural, electronic, and bonding properties of layer-structured ZnSb Dinesh Thapa, Bipin Lamichhane, Chandani Nandadasa, Junseong Song, Sung Wng Kim, Seong-Gon Kim The orthorhombic structure of Zinc Antimonide (ZnSb) that belongs to the space group Pbca has been extensively studied because of its promising thermoelectric properties. It is of great interest to study the different phases of ZnSb in order to figure out the inherent possibilities of electronic properties. We performed ab initio total-energy calculations and geometry optimizations within Density Functional Theory (DFT) using the generalized gradient approximation (GGA) Perdew–Burke–Ernzerhof (PBE) functional and the projected augmented wave (PAW) method to investigate the structural, electronic, and bonding properties of tetragonal (P4/nmm) and wurzite (P63mc) phases of layer-structured ZnSb. We calculated the charge density, electron localization function (ELF), Bader charge analysis, density of states (DOS), and band Structures of these materials. The energy barrier between tetragonal and wurzite phases has been calculated using the climbing image Nudged Elastic Band (CI-NEB) method. The screened Heyd-Scuseria-Ernzerhof (HSE) hybrid functional within the PBE functional was also applied to improve the band gap and compared to the experiment. |
Thursday, March 5, 2020 5:18PM - 5:30PM |
U43.00013: Unraveling the thermodynamic stability, catalytic activity and electronic structure of bimetallic clusters at realistic conditions Shikha Saini, Saswata Bhattacharya Cluster is considered as the prototypical system to gain a better understanding of active sites and the elementary steps of reaction mechanism at the atomistic level. Aiming toward catalytic applications, a large data set is generated on [TMxMgyOz]+/0/− clusters (TM = Cr, Fe, Co, Ni, x + y ≤ 5) using a massively parallel cascade genetic algorithm (cGA) at the hybrid density functional level of theory. The low-energy isomers are further analyzed via ab initio atomistic thermodynamics to estimate their free energy of formation at a realistic temperature T and partial pressure of oxygen pO. A thermodynamic phase diagram is drawn by minimizing the free energy of formation to identify the stable phases of [TMxMgyOz]+/0/− clusters. From this analysis, we notice that neutral and negatively charged clusters are stable in the wide range of (T, pO). The negatively charged clusters are more effective as a catalyst to lower the C−H bond activation barrier of methane. We find that the nature of TM atoms toward controlling the activation barrier is less important. However, TM gives rise to different structural motifs in the cluster, which may act as active centers for catalysis. |
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