The Experts below are selected from a list of 38424 Experts worldwide ranked by ideXlab platform
Kun Jiang - One of the best experts on this subject based on the ideXlab platform.
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unconventional high temperature superconductivity in cubic zinc blende Transition Metal Compounds
Science China-physics Mechanics & Astronomy, 2020Co-Authors: Qiang Zhang, Kun JiangAbstract:We consider possible high temperature superconductivity (high-$T_\text{c}$) in Transition Metal Compounds with a cubic zinc-blende lattice structure. When the electron filling configuration in the d-shell is close to $d^7$, all three t$_{2g}$ orbitals are near half filling with strong nearest neighbor antiferromagnetic (AFM) superexchange interactions. We argue that upon doping, this electronic environment can be one of “genes" to host unconventional high $T_\text{c}$ with a time reversal symmetry broken $d_{2z^2-x^2-y^2}\pm~{\rm~i}d_{x^2-y^2}$ pairing symmetry. With gapless nodal points along the diagonal directions, this state is a direct three-dimensional analogue to the two-dimensional B$_{1g}$ $d$-wave state in cuprates. We suggest that such a case may be realized in electron doped CoN, such as CoN$_{1-x}$O$_x$ and (H, Li)$_{1-x}$CoN.
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unconventional high temperature superconductivity in cubic zinc blende Transition Metal Compounds
arXiv: Superconductivity, 2019Co-Authors: Qiang Zhang, Kun JiangAbstract:We consider possible high temperature superconductivity (high-T$_c$) in Transition Metal Compounds with a cubic zinc-blende lattice structure. When the electron filling configuration in the d-shell is close to d$^7$, all three t$_{2g}$ orbitals are near half filling with strong nearest neighbor antiferromagnetic (AFM) superexchange interactions. We argue that upon doping, this electronic environment can be one of ``genes" to host unconventional high T$_c$ with a time reversal symmetry broken $d_{2z^2-x^2-y^2} \pm i d_{x^2-y^2}$ pairing symmetry. With gappless nodal points along the diagonal directions, this state is a direct three dimensional analogue to the two dimensional B$_{1g}$ d-wave state in cuprates. We suggest that such a case may be realized in electron doped CoN, such as CoN$_{1-x}$O$_x$ and (H, Li)$_{1-x}$CoN.
Atsushi Fujimori - One of the best experts on this subject based on the ideXlab platform.
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Systematic Aspects of The Electronic Structure of 3d Transition-Metal Compounds
Japanese Journal of Applied Physics, 1993Co-Authors: Atsushi Fujimori, Takashi Mizokawa, T. Saitoh, A. E. BocquetAbstract:Systematic changes in the electronic structure of 3d Transition-Metal Compounds with varying chemical compositions are studied by photoemission spectroscopy and configuration-interaction cluster-model analysis. The changes consist of (i) the smooth variation of model parameters such as the charge-transfer energy Δ and the d-d Coulomb repulsion energy U with atomic number and valence and (ii) the apparently irregular multiplet corrections to Δ and U, which are functions of the nominal electron number. These systematics are reflected upon the band gaps, covalency and character of doped carriers in Transition-Metal oxides and chalcogenides, and upon the optical absorption spectra and the ionization energies of substitutional Transition-Metal impurities in semiconductors.
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electronic structure of 3d Transition Metal Compounds by analysis of the 2p core level photoemission spectra
Physical Review B, 1992Co-Authors: A. E. Bocquet, T. Saitoh, T Mizokawa, H Namatame, Atsushi FujimoriAbstract:The electronic structures of a wide range of Transition-Metal Compounds, including Cu, Ni, Co, Fe, and Mn oxides and sulfides, with Metal valences ranging from 2+ to 4+, have been investigated by a cluster-type configuration-interaction analysis of the core-level 2p x-ray photoemission spectra. We show that by including the d-d exchange interaction (retaining only diagonal terms) and an anisotropic Metal-ligand hybridization in the model, these spectra can be well reproduced, and so can be used to deduce quantitatively values for the ligand-to-Metal charge-transfer energy \ensuremath{\Delta}, the on-site d-d Coulomb repulsion energy U, and the Metal-ligand transfer integrals T. Systematics for \ensuremath{\Delta} and U are generally consistent with those found from previous valence-band studies and follow expected chemical trends. By using values of \ensuremath{\Delta} and U found from this model, we show that most of the Transition-Metal Compounds studied in this work can be classified in the charge-transfer regime of the Zaanen-Sawatzky-Allen diagram. A few exceptions to these systematics have been found. Small U values found for pyrite-type ${\mathrm{CoS}}_{2}$ and ${\mathrm{FeS}}_{2}$ and large T values for Mn perovskite oxides, as well as the neglect of other mechanisms such as exciton satellites, may indicate a limitation of the local-cluster model.
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Systematics in the electronic structure of 3d Transition-Metal Compounds
Solid State Communications, 1992Co-Authors: A. E. Bocquet, Takashi Mizokawa, T. Saitoh, Atsushi FujimoriAbstract:Abstract We have studied a wide range of 3d Transition-Metal Compounds by a cluster configuration-interaction analysis of the Metal 2p core-level photoemission spectra. Deduced values for the charge-transfer energy Δ and the d-d Coulomb repulsion U, defined with respect to the multiplet-averaged energies, show a smooth variation as functions of cation atomic number, ligand and cation valence. Many physical properties, however, show apparently irregular variation, which we attribute to d-d exchange or multiplet effects, which also reflect upon Δeff and Ueff defined with respect to the lowest multiplet energies.
A. E. Bocquet - One of the best experts on this subject based on the ideXlab platform.
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Systematic Aspects of The Electronic Structure of 3d Transition-Metal Compounds
Japanese Journal of Applied Physics, 1993Co-Authors: Atsushi Fujimori, Takashi Mizokawa, T. Saitoh, A. E. BocquetAbstract:Systematic changes in the electronic structure of 3d Transition-Metal Compounds with varying chemical compositions are studied by photoemission spectroscopy and configuration-interaction cluster-model analysis. The changes consist of (i) the smooth variation of model parameters such as the charge-transfer energy Δ and the d-d Coulomb repulsion energy U with atomic number and valence and (ii) the apparently irregular multiplet corrections to Δ and U, which are functions of the nominal electron number. These systematics are reflected upon the band gaps, covalency and character of doped carriers in Transition-Metal oxides and chalcogenides, and upon the optical absorption spectra and the ionization energies of substitutional Transition-Metal impurities in semiconductors.
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electronic structure of 3d Transition Metal Compounds by analysis of the 2p core level photoemission spectra
Physical Review B, 1992Co-Authors: A. E. Bocquet, T. Saitoh, T Mizokawa, H Namatame, Atsushi FujimoriAbstract:The electronic structures of a wide range of Transition-Metal Compounds, including Cu, Ni, Co, Fe, and Mn oxides and sulfides, with Metal valences ranging from 2+ to 4+, have been investigated by a cluster-type configuration-interaction analysis of the core-level 2p x-ray photoemission spectra. We show that by including the d-d exchange interaction (retaining only diagonal terms) and an anisotropic Metal-ligand hybridization in the model, these spectra can be well reproduced, and so can be used to deduce quantitatively values for the ligand-to-Metal charge-transfer energy \ensuremath{\Delta}, the on-site d-d Coulomb repulsion energy U, and the Metal-ligand transfer integrals T. Systematics for \ensuremath{\Delta} and U are generally consistent with those found from previous valence-band studies and follow expected chemical trends. By using values of \ensuremath{\Delta} and U found from this model, we show that most of the Transition-Metal Compounds studied in this work can be classified in the charge-transfer regime of the Zaanen-Sawatzky-Allen diagram. A few exceptions to these systematics have been found. Small U values found for pyrite-type ${\mathrm{CoS}}_{2}$ and ${\mathrm{FeS}}_{2}$ and large T values for Mn perovskite oxides, as well as the neglect of other mechanisms such as exciton satellites, may indicate a limitation of the local-cluster model.
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Systematics in the electronic structure of 3d Transition-Metal Compounds
Solid State Communications, 1992Co-Authors: A. E. Bocquet, Takashi Mizokawa, T. Saitoh, Atsushi FujimoriAbstract:Abstract We have studied a wide range of 3d Transition-Metal Compounds by a cluster configuration-interaction analysis of the Metal 2p core-level photoemission spectra. Deduced values for the charge-transfer energy Δ and the d-d Coulomb repulsion U, defined with respect to the multiplet-averaged energies, show a smooth variation as functions of cation atomic number, ligand and cation valence. Many physical properties, however, show apparently irregular variation, which we attribute to d-d exchange or multiplet effects, which also reflect upon Δeff and Ueff defined with respect to the lowest multiplet energies.
Riidiger Bormann - One of the best experts on this subject based on the ideXlab platform.
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catalytic mechanism of Transition Metal Compounds on mg hydrogen sorption reaction
Journal of Physical Chemistry B, 2006Co-Authors: Gagik Barkhordarian, Thomas Klassen, Riidiger BormannAbstract:The catalytic mechanisms of Transition-Metal Compounds during the hydrogen sorption reaction of magnesium-based hydrides were investigated through relevant experiments. Catalytic activity was found to be influenced by four distinct physico-thermodynamic properties of the Transition-Metal compound: a high number of structural defects, a low stability of the compound, which however has to be high enough to avoid complete reduction of the Transition Metal under operating conditions, a high valence state of the Transition-Metal ion within the compound, and a high affinity of the Transition-Metal ion to hydrogen. On the basis of these results, further optimization of the selection of catalysts for improving sorption properties of magnesium-based hydrides is possible. In addition, utilization of Transition-Metal Compounds as catalysts for other hydrogen storage materials is considered.
K.h.j. Buschow - One of the best experts on this subject based on the ideXlab platform.
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The free‐powder magnetization of ferrimagnetic rare‐earth Transition‐Metal Compounds
Journal of Applied Physics, 1993Co-Authors: Z. G. Zhao, P.f. De Châtel, F.r. De Boer, K.h.j. BuschowAbstract:Magnetization curves have been calculated for single crystals of ferrimagnetic rare‐earth Transition‐Metal Compounds that are free to rotate in the applied magnetic field. The calculations have been performed taking into account the magnetic‐anisotropy constants of the rare‐earth and Transition‐Metal sublattices up to the fourth order. Seven different types of rotation processes can be distinguished.
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The free-powder magnetization of ferrimagnetic rare-earth-Transition-Metal Compounds
Journal of Magnetism and Magnetic Materials, 1993Co-Authors: Z. G. Zhao, P.f. De Châtel, F.r. De Boer, J.h.v.j. Brabers, K.h.j. BuschowAbstract:Magnetization curves have been calculated for single crystals of ferrimagnetic rare-earth Transition-Metal Compounds that are free to rotate in the applied magnetic field. The calculations have been performed taking into account the magnetic-anisotropy constants of the rare-earth and Transition-Metal sublattices up to the fourth order. Seven different types of rotation processes can be distinguished.