Erratum: “Energies of the X- and L-valleys in In{sub 0.53}Ga{sub 0.47}As from electronic structure calculations” [J. Appl. Phys. 119, 055707 (2016)]
No abstract prepared.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
SEARCH · Engineering Papers
Results for “Electronic Structure”
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Antiferromagnetic structures and electronic energy levels at reconstructed NiO(111) surfaces: A DFT + U study
In this work, we studied how the surface reconstruction and passivation influence the antiferromagnetic and electronic structures of NiO(111) surface using first-principles electronic structure calculations. These features lead to a surprisingly wide variety of different surface electronic structures, and some surfaces are even metallic. Different reconstructions and surface passivation were also found to qualitatively alter the charge-transfer band gap type of bulk NiO. At the same time, the antiferromagnetic character of bulk NiO in the 111 direction is retained even near the surface, and the magnetic moment quickly converges to the bulk value within a few surface layers.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Detection of spin-resolved electronic structures from a buried ferromagnetic layer utilizing forward Mott scattering
We report ultrahigh-resolution spin-resolved hard X-ray photoemission (HAXPES) for a buried FeNi alloy film. By utilizing the forward Mott scattering in a Au layer on FeNi, our spin-resolved HAXPES method does not require a standard spin detector and allows us to use the multi-channel electron detection system for the high-efficient electron detection as used in conventional photoemission spectroscopy. A combination of the forward Mott scattering and multi-channel detection leads us to measure a clear spin polarization as well as spin-resolved majority and minority states in the Fe 2p core-level spectra without using the standard spin detector. This method enables us to measure spin-resolved core-level spectra for buried ferromagnetic materials.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
Electronic structure, magnetic properties, spin orientation, and doping effect in Mn 3 Si 2 Te 6
The layered material Mn 3 Si 2 Te 6 , with alternating stacking honeycomb and triangular layers, is attracting considerable attention due to its rich physical properties. Here, in this study, using density functional theory and classical Monte Carlo (MC) methods, we systematically study this system with the 3d 5 electronic configuration. Near the Fermi level, the states are mainly contributed by Te 5p orbitals hybridized with Mn 3d orbitals, resembling a charge-transfer system. Furthermore, the spin orientations of the ferrimagnetic (FiM) ground state display different conductive behaviors when along the ab plane or out-of-plane directions: insulating vs metallic states. The energy difference between the FiM [110] insulating and FiM [001] metallic phases is very small (~0.71 meV/Mn) . Changing the angle θ of spin orientation from in-plane to out-of-plane directions, the band gaps of this system are gradually reduced, leading to an insulator-metal transition, resulting in an enhanced electrical conductivity, related to the colossal angular magnetoresistance (MR) effect. Although the three main magnetic couplings were found to be antiferromagnetic, overall the ground state is FiM. In addition, we also constructed the magnetic phase diagram using the classical XY spin model studied with the MC method. Three magnetic phases were obtained, including antiferromagnetic order, noncollinear spin patterns, and FiM order. Moreover, we also investigated the Se and Ge doping into the Mn 3 Si 2 Te 6 system: the FiM state has the lowest energy among the magnetic candidates for both Se- and Ge-doped cases. The magnetic anisotropy energy (MAE) decreases in the Se-doped case because the Mn orbital moment is reduced as the doping x increases. Due to the small spin-orbit-coupling effect of Se, the insulator-metal transition caused by the spin orientation disappears in the Se-doped case, resulting in an insulating phase in the FiM [001] phase. This causes a reduced colossal angular MR. However, both the MAE and the band gap of the Ge-doped case do not change much with increasing doping x . Our results for Mn 3 Si 2 Te 6 could provide guidance to experimentalists and theorists working on this system or related materials.
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
Capturing Coupled Structural and Electronic Motions During Excited-State Intramolecular Proton Transfer via Computational Multiedge Resonant Inelastic X-ray Scattering
Proton-transfer processes build the foundation of many chemical processes. In Excited State Intramolecular Proton Transfer (ESIPT) processes the proton transfer process is impulsively started through light. Here, in this study, we explore the changes in coupled atomic and electronic motions during and following ESIPT through computational time-resolved Resonant Inelastic X-ray Scattering (trRIXS). Excited-state Ab Initio Molecular Dynamics (AIMD) simulations combined with Time-Dependent Density Functional Theory (TDDFT) calculations were performed for 10-hydroxybenzo[h]quinoline to obtain trRIXS signatures. RIXS at both the nitrogen and oxygen K-edges were computed to resolve the dynamics electronic structure from both the proton donor and acceptor perspective. The results show how RIXS can reveal the local electronic structure, the coupling between different electronic states and how electronic structure and coupling change during the proton transfer process. Additionally, we observe a strong correlation between spectral changes and structural changes during ESIPT.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Intrinsic relationship between electronic structures and phase transition of SrBi{sub 2−x}Nd{sub x}Nb{sub 2}O{sub 9} ceramics from ultraviolet ellipsometry at elevated temperatures
The ferroelectric orthorhombic to paraelectric tetragonal phase transition of SrBi{sub 2−x}Nd{sub x}Nb{sub 2}O{sub 9} (x = 0, 0.05, 0.1, and 0.2) layer-structured ceramics has been investigated by temperature-dependent spectroscopic ellipsometry. Based on the analysis of dielectric functions from 0 to 500 °C with double Tauc-Lorentz dispersion model, the interband transitions located at ultraviolet region have shown an abrupt variation near the Curie temperature. The changes of dielectric functions are mainly due to the thermal-optical and/or photoelastic effect. Moreover, the characteristic alteration in interband transitions can be ascribed to distortion of NbO{sub 6} octahedron and variation of hybridization between Bi 6s and O 2p states during the structure transformation.
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
Erratum: “Electronic structure of CeO studied by a four-component relativistic configuration interaction method” [J. Chem. Phys. 138, 224310 (2013)]
No abstract prepared.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Probing Electronic Structure at Magnetoelectric Interfaces
No abstract prepared.
36 MATERIALS SCIENCE↗
Hydrogen diffusion and electronic structure in crystalline and amorphous Ti/sub y/CuH/sub x/
Hydrogen diffusion behavior and electronic properties of crystalline TiCuHo94, Ti2CuH1.90, and Ti2CuH2.63 and amorphous a-TiCuH1.4 were studied using proton relaxation times, proton Knight shifts, and magnetic susceptibilities. Crystal structure and hydrogen site occupancy have major roles in hydrogen mobility. The density of electron states at E sub F is reduced in amorphous a-TiCuH1.4 compared to the crystalline hydrides.
Bowman, R. C., Jr.↗
Quasiparticle electronic structure and optical absorption of diamond nanoparticles from ab initio many-body perturbation theory
The excited states of small-diameter diamond nanoparticles in the gas phase are studied using the GW method and Bethe-Salpeter equation (BSE) within the ab initio many-body perturbation theory. The calculated ionization potentials and optical gaps are in agreement with experimental results, with the average error about 0.2 eV. The electron affinity is negative and the lowest unoccupied molecular orbital is rather delocalized. Precise determination of the electron affinity requires one to take the off-diagonal matrix elements of the self-energy operator into account in the GW calculation. BSE calculations predict a large exciton binding energy which is an order of magnitude larger than that in the bulk diamond.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Electronic structure, dimer physics, orbital-selective behavior, and magnetic tendencies in the bilayer nickelate superconductor $\mathrm{La_3Ni_2O_7}$under pressure
Motivated by the recently reported high-temperature superconductivity in the bilayer La 3 Ni 2 O 7 (LNO) under pressure, we comprehensively study this system using ab initio techniques. The Ni 3d orbitals have a large bandwidth at ambient pressure, increasing by ~22% at 29.5 GPa. Without electronic interactions, the Ni d 3z 2 -r 2 orbitals form a bonding-antibonding molecular orbital state via the O p z inducing a “dimer” lattice in the LNO bilayers. The Fermi surface consists of two-electron sheets with mixed e g orbitals and a hole pocket defined by the d 3z 2 -r 2 orbital, suggesting a Ni two-orbital minimum model. Different from the infinite-layer nickelate, we obtained a large interorbital hopping between d 3z 2 -r 2 and d x 2 -y 2 states in LNO, caused by the ligand “bridge” of in-plane O p x or p y orbitals connecting those two orbitals, inducing d-p σ-bonding characteristics. The competition between the intraorbital and interorbital hoppings leads to an interesting dominant spin stripe (π,0) order because of bond ferromagnetic tendencies via the recently discussed “half-empty” mechanism.
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
Electronic Structure and Optical Properties of α-CH3NH3PbBr3 Perovskite Single Crystal.
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14 SOLAR ENERGY↗
The electronic structure of an S-pair in barrier-less metal/silicon junctions
With S atoms doping into a bulk Si, it is revealed through first principles calculations that the highly S concentrated bulk Si is metallic. S atoms can be highly doped in the bulk Si because an S-pair located face to face in adjacent Si lattice sites gains a large energy and forms sp{sup 2} + p{sub z} electronic configurations and extra donor electrons. Schottky junction will be thus barrier-less by the Si metallization, well agreeing with experimental analyses.
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
Electronic Structure Studies of 200 MeV Ag{sup +15} Swift Heavy Ion Irradiated SnO{sub 2} Thin Films Using X-Ray Absorption Spectroscopy
Tin dioxide (SnO{sub 2}) thin films were deposited on a well cleaned sapphire single crystal substrate by rf magnetron sputtering technique. After deposition, films were irradiated by swift heavy ion (SHI) irradiation at various ion fluences. We present the X-ray absorption spectra (XAS) at the oxygen K- and Sn M{sub 5,4,} edge. The XAS pattern reveals the broadening of O K- and Sn M{sub 5,4,} edge features with increasing ion fluence. The fraction of under-coordinated surface atoms in the SnO{sub 2} thin films increases, which is attributed to the structural distortions induced by SHI irradiations.
36 MATERIALS SCIENCE↗
Tuning the electronic structure of Ag-Pd alloys to enhance performance for alkaline oxygen reduction
Alloying is a powerful tool that can improve the electrocatalytic performance and viability of diverse electrochemical renewable energy technologies. Herein, we enhance the activity of Pd-based electrocatalysts via Ag-Pd alloying while simultaneously lowering precious metal content in a broad-range compositional study focusing on highly comparable Ag-Pd thin films synthesized systematically via electron-beam physical vapor co-deposition. Cyclic voltammetry in 0.1 M KOH shows enhancements across a wide range of alloys; even slight alloying with Ag (e.g. Ag 0.1 Pd 0.9 ) leads to intrinsic activity enhancements up to 5-fold at 0.9 V vs. RHE compared to pure Pd. Based on density functional theory and x-ray absorption, we hypothesize that these enhancements arise mainly from ligand effects that optimize adsorbate–metal binding energies with enhanced Ag-Pd hybridization. This work shows the versatility of coupled experimental-theoretical methods in designing materials with specific and tunable properties and aids the development of highly active electrocatalysts with decreased precious-metal content.
25 ENERGY STORAGE↗
Comment on “Underlying simplicity of 5f unoccupied electronic structure” [J. Vac. Sci. Technol. A 39, 043205 (2021)]
Abstract not provided.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Electronic structure studies of Fe doped CeO{sub 2} thin films by resonance photoemission spectroscopy
We have studied the modification in the electronic properties of pulsed laser deposited CeO{sub 2} thin films due to Fe doping (2 and 6 at %), with the help of x-ray photoemission spectroscopy (XPS) and resonance photoemission spectroscopy (RPES) measurements. XPS results indicate the ionic state of Fe in the Fe doped films, ruling out the possibility of Fe metallic clusters. Valence band spectra of CeO{sub 2} show an additional feature after Fe doping, suggesting its incorporation in the CeO{sub 2} matrix. RPES studies on these films reveal the hybridization between oxygen vacancy induced Ce localized states and Fe derived states.
36 MATERIALS SCIENCE↗