The Experts below are selected from a list of 417030 Experts worldwide ranked by ideXlab platform
Akiko Kobayashi - One of the best experts on this subject based on the ideXlab platform.
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single component molecular conductor pt dmdt 2 a three dimensional ambient pressure molecular dirac Electron System
Chemical Communications, 2019Co-Authors: Biao Zhou, Eiji Nishibori, Shoji Ishibashi, Tatsuru Ishii, Takahiko Sekine, Ryosuke Takehara, Kazuya Miyagawa, Kazushi Kanoda, Akiko KobayashiAbstract:The single-component molecular conductor [Pt(dmdt)2] is a sought-after ambient-pressure molecular Dirac Electron System, which exhibits a high temperature-insensitive conductivity and temperature-dependent magnetic susceptibility nearly vanishing below 120 K. First-principles DFT calculations reveal that Dirac cones emerge along the a* direction, and form Dirac nodal lines.
Takao Tsumuraya - One of the best experts on this subject based on the ideXlab platform.
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ambient pressure dirac Electron System in the quasi two dimensional molecular conductor α bets 2 i 3
Physical Review B, 2021Co-Authors: Shunsuke Kitou, Takao Tsumuraya, Hikaru Sawahata, Fumiyuki Ishii, K Hiraki, Toshikazu Nakamura, Naoyuki Katayama, Hiroshi SawaAbstract:We investigated the precise crystal structures and Electronic states of a quasi-two-dimensional molecular conductor $\ensuremath{\alpha}\text{\ensuremath{-}}{(\mathrm{BETS})}_{2}{\mathrm{I}}_{3}$ at ambient pressure. The Electronic resistivity of this molecular solid shows metal-to-insulator (MI) crossover behavior at ${T}_{\mathrm{MI}}=50\phantom{\rule{4pt}{0ex}}\mathrm{K}$. Our x-ray diffraction and $^{13}\mathrm{C}$ nuclear magnetic resonance experiments revealed that $\ensuremath{\alpha}\text{\ensuremath{-}}{(\mathrm{BETS})}_{2}{\mathrm{I}}_{3}$ maintains the inversion symmetry below ${T}_{\mathrm{MI}}$. First-principles calculations found a pair of anisotropic Dirac cones at a general $k$ point, with the degenerate contact points at the Fermi level. The origin of the insulating state in this System is a small energy gap of $\ensuremath{\sim}2\phantom{\rule{0.16em}{0ex}}\mathrm{meV}$ opened by the spin-orbit interaction. The ${Z}_{2}$ topological invariants indicate that this System is a weak topological insulator. Our results suggest that $\ensuremath{\alpha}\text{\ensuremath{-}}{(\mathrm{BETS})}_{2}{\mathrm{I}}_{3}$ is a promising material for studying the bulk Dirac Electron System in two dimensions.
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emergence of the dirac Electron System in a single component molecular conductor under high pressure
Journal of the American Chemical Society, 2017Co-Authors: Reizo Kato, Takao Tsumuraya, Tsuyoshi Miyazaki, Yoshikazu SuzumuraAbstract:Single-component molecular conductors can provide a variety of Electronic states. We demonstrate here that the Dirac Electron System emerges in a single-component molecular conductor under high pressure. First-principles density functional theory calculations revealed that Dirac cones are formed in the single-component molecular conductor [Pd(dddt)2] (dddt = 5,6-dihydro-1,4-dithiin-2,3-dithiolate), which shows temperature-independent resistivity (zero-gap behavior) at 12.6 GPa. The Dirac cone formation in [Pd(dddt)2] can be understood by a tight-binding model. The Dirac points originate from the HOMO and LUMO bands, each of which is associated with different molecular layers. Overlap of these two bands provides a closed intersection at the Fermi level (Fermi line) if there is no HOMO–LUMO coupling. Two-step HOMO–LUMO couplings remove the degeneracy on the Fermi line, resulting in gap formation. The Dirac cones emerge at the points where the Fermi line intersects with a line on which the HOMO–LUMO coupling...
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Emergence of the Dirac Electron System in a Single-Component Molecular Conductor under High Pressure
2017Co-Authors: Reizo Kato, Takao Tsumuraya, Tsuyoshi Miyazaki, Hengbo Cui, Yoshikazu SuzumuraAbstract:Single-component molecular conductors can provide a variety of Electronic states. We demonstrate here that the Dirac Electron System emerges in a single-component molecular conductor under high pressure. First-principles density functional theory calculations revealed that Dirac cones are formed in the single-component molecular conductor [Pd(dddt)2] (dddt = 5,6-dihydro-1,4-dithiin-2,3-dithiolate), which shows temperature-independent resistivity (zero-gap behavior) at 12.6 GPa. The Dirac cone formation in [Pd(dddt)2] can be understood by a tight-binding model. The Dirac points originate from the HOMO and LUMO bands, each of which is associated with different molecular layers. Overlap of these two bands provides a closed intersection at the Fermi level (Fermi line) if there is no HOMO–LUMO coupling. Two-step HOMO–LUMO couplings remove the degeneracy on the Fermi line, resulting in gap formation. The Dirac cones emerge at the points where the Fermi line intersects with a line on which the HOMO–LUMO coupling is zero
Yoshikazu Suzumura - One of the best experts on this subject based on the ideXlab platform.
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emergence of the dirac Electron System in a single component molecular conductor under high pressure
Journal of the American Chemical Society, 2017Co-Authors: Reizo Kato, Takao Tsumuraya, Tsuyoshi Miyazaki, Yoshikazu SuzumuraAbstract:Single-component molecular conductors can provide a variety of Electronic states. We demonstrate here that the Dirac Electron System emerges in a single-component molecular conductor under high pressure. First-principles density functional theory calculations revealed that Dirac cones are formed in the single-component molecular conductor [Pd(dddt)2] (dddt = 5,6-dihydro-1,4-dithiin-2,3-dithiolate), which shows temperature-independent resistivity (zero-gap behavior) at 12.6 GPa. The Dirac cone formation in [Pd(dddt)2] can be understood by a tight-binding model. The Dirac points originate from the HOMO and LUMO bands, each of which is associated with different molecular layers. Overlap of these two bands provides a closed intersection at the Fermi level (Fermi line) if there is no HOMO–LUMO coupling. Two-step HOMO–LUMO couplings remove the degeneracy on the Fermi line, resulting in gap formation. The Dirac cones emerge at the points where the Fermi line intersects with a line on which the HOMO–LUMO coupling...
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Emergence of the Dirac Electron System in a Single-Component Molecular Conductor under High Pressure
2017Co-Authors: Reizo Kato, Takao Tsumuraya, Tsuyoshi Miyazaki, Hengbo Cui, Yoshikazu SuzumuraAbstract:Single-component molecular conductors can provide a variety of Electronic states. We demonstrate here that the Dirac Electron System emerges in a single-component molecular conductor under high pressure. First-principles density functional theory calculations revealed that Dirac cones are formed in the single-component molecular conductor [Pd(dddt)2] (dddt = 5,6-dihydro-1,4-dithiin-2,3-dithiolate), which shows temperature-independent resistivity (zero-gap behavior) at 12.6 GPa. The Dirac cone formation in [Pd(dddt)2] can be understood by a tight-binding model. The Dirac points originate from the HOMO and LUMO bands, each of which is associated with different molecular layers. Overlap of these two bands provides a closed intersection at the Fermi level (Fermi line) if there is no HOMO–LUMO coupling. Two-step HOMO–LUMO couplings remove the degeneracy on the Fermi line, resulting in gap formation. The Dirac cones emerge at the points where the Fermi line intersects with a line on which the HOMO–LUMO coupling is zero
Stephen G Dale - One of the best experts on this subject based on the ideXlab platform.
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extreme density driven delocalization error for a model solvated Electron System
Journal of Chemical Physics, 2013Co-Authors: Erin R Johnson, Alberto Oterodelaroza, Stephen G DaleAbstract:Delocalization (or charge-transfer) error is one of the scarce but spectacular failures of density-functional theory. It is particularly apparent in extensively delocalized molecules, and manifests in the calculation of bandgaps, reaction barriers, and dissociation limits. Even though delocalization error is always present in the self-consistent Electron density, the differences from reference densities are often quite subtle and the error tends to be driven by the exchange-correlation energy expression. In this article, we propose a model System (the Kevan model) where approximate density functionals predict dramatically different charge distributions because of delocalization error. The model System consists of an Electron trapped in a water hexamer and is a finite representation of an experimentally observed class of solids: electrides. The Kevan model is of fundamental interest because it allows the estimation of charge transfer error without recourse to fractional charge calculations, but our results are also relevant in the context of the modeling of confined Electrons in density-functional theory.
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extreme density driven delocalization error for a model solvated Electron System
Journal of Chemical Physics, 2013Co-Authors: Erin R Johnson, Alberto Oterodelaroza, Stephen G DaleAbstract:Delocalization (or charge-transfer) error is one of the scarce but spectacular failures of density-functional theory. It is particularly apparent in extensively delocalized molecules, and manifests in the calculation of bandgaps, reaction barriers, and dissociation limits. Even though delocalization error is always present in the self-consistent Electron density, the differences from reference densities are often quite subtle and the error tends to be driven by the exchange-correlation energy expression. In this article, we propose a model System (the Kevan model) where approximate density functionals predict dramatically different charge distributions because of delocalization error. The model System consists of an Electron trapped in a water hexamer and is a finite representation of an experimentally observed class of solids: electrides. The Kevan model is of fundamental interest because it allows the estimation of charge transfer error without recourse to fractional charge calculations, but our results...
M S Bahramy - One of the best experts on this subject based on the ideXlab platform.
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interplay of spin orbit coupling and coulomb interaction in zno based Electron System
Nature Communications, 2021Co-Authors: D Maryenko, Minoru Kawamura, A Ernst, V K Dugaev, Ya E Sherman, M Kriener, M S BahramyAbstract:Spin–orbit coupling (SOC) is pivotal for various fundamental spin-dependent phenomena in solids and their technological applications. In semiconductors, these phenomena have been so far studied in relatively weak Electron–Electron interaction regimes, where the single Electron picture holds. However, SOC can profoundly compete against Coulomb interaction, which could lead to the emergence of unconventional Electronic phases. Since SOC depends on the electric field in the crystal including contributions of itinerant Electrons, Electron–Electron interactions can modify this coupling. Here we demonstrate the emergence of the SOC effect in a high-mobility two-dimensional Electron System in a simple band structure MgZnO/ZnO semiconductor. This Electron System also features strong Electron–Electron interaction effects. By changing the carrier density with Mg-content, we tune the SOC strength and achieve its interplay with Electron–Electron interaction. These Systems pave a way to emergent spintronic phenomena in strong Electron correlation regimes and to the formation of quasiparticles with the Electron spin strongly coupled to the density. The coexistence of spin–orbit and Electron–Electron interactions is expected to give rise to novel Electronic phases and spin textures, but it is challenging to achieve in experiments. Here the authors realize such a regime in a two-dimensional Electron System at a MgZnO/ZnO interface, by tuning the carrier density.
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interplay of spin orbit coupling and coulomb interaction in zno based Electron System
arXiv: Mesoscale and Nanoscale Physics, 2020Co-Authors: D Maryenko, Minoru Kawamura, A Ernst, V K Dugaev, Ya E Sherman, M Kriener, M S BahramyAbstract:Spin-orbit coupling (SOC) is pivotal for various fundamental spin-dependent phenomena in solids and their technological applications. In semiconductors, these phenomena have been so far studied in relatively weak Electron-Electron interaction regimes, where the single Electron picture holds. However, SOC can profoundly compete against Coulomb interaction, which could lead to the emergence of unconventional Electronic phases. Since SOC depends on the electric field in the crystal including contributions of itinerant Electrons, Electron-Electron interactions can modify this coupling. Here we demonstrate the emergence of SOC effect in a high-mobility two-dimensional Electron System in a simple band structure MgZnO/ZnO semiconductor. This Electron System features also strong Electron-Electron interaction effects. By changing the carrier density with Mg-content, we tune the SOC strength and achieve its interplay with Electron-Electron interaction. These Systems pave a way to emergent spintronic phenomena in strong Electron correlation regime and to the formation of novel quasiparticles with the Electron spin strongly coupled to the density.