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Li RS, He YS, Cao ZL, Liu ZY, Wang YM, Li S, Xie Z. Valence Fluctuation of Uranium Ions in Uranium Sesquinitride Revealed by Dynamical Mean-field Theory Merged with Density Functional Theory. Chemphyschem 2023; 24:e202300242. [PMID: 37369624 DOI: 10.1002/cphc.202300242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 06/25/2023] [Accepted: 06/27/2023] [Indexed: 06/29/2023]
Abstract
The electronic properties, in particular, the occupation number of 5f electrons and the valence state of U ions in uranium sesquinitride (U2 N3 ) are studied by using density functional theory (DFT) calculations merged with dynamical mean-field theory (DMFT). The results demonstrate that j=5/2 and j=7/2 manifolds are in the weakly correlated metallic and weakly correlated insulating regimes, respectively. The quasi-particle weights indicate that LS coupling scheme is more feasible for 5f electrons, which are not in the orbital-selective localized state. The weighted summation of the occupation probabilities of 5fn (n=0,1,2,3,4) atomic configurations suggests that 5f electrons have the inter-configuration fluctuation, or the mixed-valence state for U ions, together with an average occupation number of 5f electrons n5f ∼2.234, which is in good agreement with the electron localization function (ELF) and occupation analysis based on other DFT-based calculations. The 5fn -mixing-driven inter-configuration fluctuation might originate from the dual nature of 5f electrons, and the flexible electronic configuration of U ions. Finally, the so-called quasiparticle band structure is also discussed.
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Affiliation(s)
- Ru-Song Li
- Shaanxi International Joint Research Center for Applied Technology of Controllable Neutron Source, School of Electronic Information, Xijing University, Xi'an, 710123, China
| | - Yu-Song He
- Shaanxi International Joint Research Center for Applied Technology of Controllable Neutron Source, School of Electronic Information, Xijing University, Xi'an, 710123, China
| | - Ze-Lin Cao
- Shaanxi International Joint Research Center for Applied Technology of Controllable Neutron Source, School of Electronic Information, Xijing University, Xi'an, 710123, China
| | - Zhi-Yong Liu
- Research Institute of Beijing High Technology, Beijing, 100077, China
| | - Yuan-Ming Wang
- Research Institute of Beijing High Technology, Beijing, 100077, China
| | - Sheng Li
- Shaanxi International Joint Research Center for Applied Technology of Controllable Neutron Source, School of Electronic Information, Xijing University, Xi'an, 710123, China
| | - Zheng Xie
- College of Rare Earth and Faculty of Materials Metallurgy and Chemistry, Jiangxi University of Science and Technology, Ganzhou, 341000, P. R. China
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Liu C, Kreisel A, Zhong S, Li Y, Andersen BM, Hirschfeld P, Wang J. Orbital-Selective High-Temperature Cooper Pairing Developed in the Two-Dimensional Limit. Nano Lett 2022; 22:3245-3251. [PMID: 35416679 DOI: 10.1021/acs.nanolett.1c04863] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
For multiband superconductors, the orbital multiplicity yields orbital differentiation in normal-state properties and can lead to orbital-selective spin-fluctuation Cooper pairing. The orbital-selective phenomenon has become increasingly pivotal in clarifying the pairing "enigma", particularly for multiband high-temperature superconductors. Meanwhile, in one-unit-cell (1-UC) FeSe/SrTiO3, since the standard electron-hole Fermi pocket nesting scenario is inapplicable, the actual pairing mechanism is subject to intense debate. Here, by measuring high-resolution Bogoliubov quasiparticle interference, we report observations of highly anisotropic magnetic Cooper pairing in 1-UC FeSe. Theoretically, it is important to incorporate orbitally selective effects of electronic correlations within a spin-fluctuation pairing calculation, where the dxy orbital becomes coherence-suppressed. The resulting pairing gap is compatible with the experimental findings, which suggests that high-Tc Cooper pairing with orbital selectivity applies to 2D-limit 1-UC FeSe. Our findings imply the general existence of orbital selectivity in iron-based superconductors and the universal significance of electron correlations in high-Tc superconductors.
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Affiliation(s)
- Chaofei Liu
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, People's Republic of China
| | - Andreas Kreisel
- Institut für Theoretische Physik, Universität Leipzig, D-04103 Leipzig, Germany
| | - Shan Zhong
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, People's Republic of China
| | - Yu Li
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, People's Republic of China
| | - Brian M Andersen
- Niels Bohr Institute, University of Copenhagen, Jagtvej 128, DK-2200 Copenhagen, Denmark
| | - Peter Hirschfeld
- Department of Physics, University of Florida, Gainesville, Florida 32611, United States
| | - Jian Wang
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, People's Republic of China
- CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- Beijing Academy of Quantum Information Sciences, Beijing 100193, People's Republic of China
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Zhang MY, Jiang H. Accurate Prediction of Band Structure of FeS 2: A Hard Quest of Advanced First-Principles Approaches. Front Chem 2021; 9:747972. [PMID: 34650959 PMCID: PMC8506039 DOI: 10.3389/fchem.2021.747972] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 09/14/2021] [Indexed: 11/13/2022] Open
Abstract
The pyrite and marcasite polymorphs of FeS2 have attracted considerable interests for their potential applications in optoelectronic devices because of their appropriate electronic and optical properties. Controversies regarding their fundamental band gaps remain in both experimental and theoretical materials research of FeS2. In this work, we present a systematic theoretical investigation into the electronic band structures of the two polymorphs by using many-body perturbation theory with the GW approximation implemented in the full-potential linearized augmented plane waves (FP-LAPW) framework. By comparing the quasi-particle (QP) band structures computed with the conventional LAPW basis and the one extended by high-energy local orbitals (HLOs), denoted as LAPW + HLOs, we find that one-shot or partially self-consistent GW (G 0 W 0 and GW 0, respectively) on top of the Perdew-Burke-Ernzerhof (PBE) generalized gradient approximation with a converged LAPW + HLOs basis is able to remedy the artifact reported in the previous GW calculations, and leads to overall good agreement with experiment for the fundamental band gaps of the two polymorphs. Density of states calculated from G 0 W 0@PBE with the converged LAPW + HLOs basis agrees well with the energy distribution curves from photo-electron spectroscopy for pyrite. We have also investigated the performances of several hybrid functionals, which were previously shown to be able to predict band gaps of many insulating systems with accuracy close or comparable to GW. It is shown that the hybrid functionals considered in general fail badly to describe the band structures of FeS2 polymorphs. This work indicates that accurate prediction of electronic band structure of FeS2 poses a stringent test on state-of-the-art first-principles approaches, and the G 0 W 0 method based on semi-local approximation performs well for this difficult system if it is practiced with well-converged numerical accuracy.
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Affiliation(s)
| | - Hong Jiang
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing, China
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Sihi A, Pandey SK. Investigating the effect of temperature dependent many-body interactions on electronic structures of SnTe in the Matsubara-time domain. J Phys Condens Matter 2021; 33:225505. [PMID: 33684906 DOI: 10.1088/1361-648x/abeca8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 03/08/2021] [Indexed: 06/12/2023]
Abstract
Recently, SnTe has gained attention due to its non-trivial topological nature and eco-friendly thermoelectric applications. We report a detailed temperature dependent electronic structure of this compound using DFT andGWmethods. The calculated values of bandgaps by using PBEsol andG0W0methods are found to be in good agreement with the experiment, whereas mBJ underestimates the bandgap. The averaged value of diagonal matrix elements of fully screened Coulomb interaction (W̄) atω= 0 eV for Sn (Te) 5porbitals is ∼1.39 (∼1.70) eV. The nature of frequency dependentW̄(ω)reveals that the correlation strength of this compound is relatively weaker and hence the excited electronic state can be properly studied by full-GWmany-body technique. The plasmon excitation is found to be important in understanding this frequency dependentW̄(ω). The temperature dependent electron-electron interactions (EEI) reduces the bandgaps with increasing temperature. The value of bandgap at 300 K is obtained to be ∼161 meV. The temperature dependent lifetimes of electronic state alongW-L-Γ direction are also estimated. This work suggests that EEI is important to explain the high temperature transport behaviour of SnTe.
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Affiliation(s)
- Antik Sihi
- School of Basic Sciences, Indian Institute of Technology Mandi, Kamand-175075, India
| | - Sudhir K Pandey
- School of Engineering, Indian Institute of Technology Mandi, Kamand-175075, India
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Jeong K, Park KW, Kim J. Relative Entropy as a Measure of Difference between Hermitian and Non-Hermitian Systems. Entropy (Basel) 2020; 22:E809. [PMID: 33286580 DOI: 10.3390/e22080809] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 07/16/2020] [Accepted: 07/22/2020] [Indexed: 11/30/2022]
Abstract
We employ the relative entropy as a measure to quantify the difference of eigenmodes between Hermitian and non-Hermitian systems in elliptic optical microcavities. We have found that the average value of the relative entropy in the range of the collective Lamb shift is large, while that in the range of self-energy is small. Furthermore, the weak and strong interactions in the non-Hermitian system exhibit rather different behaviors in terms of the relative entropy, and thus it displays an obvious exchange of eigenmodes in the elliptic microcavity.
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Abstract
The GW approximation in electronic structure theory has become a widespread tool for predicting electronic excitations in chemical compounds and materials. In the realm of theoretical spectroscopy, the GW method provides access to charged excitations as measured in direct or inverse photoemission spectroscopy. The number of GW calculations in the past two decades has exploded with increased computing power and modern codes. The success of GW can be attributed to many factors: favorable scaling with respect to system size, a formal interpretation for charged excitation energies, the importance of dynamical screening in real systems, and its practical combination with other theories. In this review, we provide an overview of these formal and practical considerations. We expand, in detail, on the choices presented to the scientist performing GW calculations for the first time. We also give an introduction to the many-body theory behind GW, a review of modern applications like molecules and surfaces, and a perspective on methods which go beyond conventional GW calculations. This review addresses chemists, physicists and material scientists with an interest in theoretical spectroscopy. It is intended for newcomers to GW calculations but can also serve as an alternative perspective for experts and an up-to-date source of computational techniques.
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Affiliation(s)
- Dorothea Golze
- Department of Applied Physics, Aalto University, School of Science, Espoo, Finland
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Casals-Sainz JL, Castro AC, Francisco E, Pendás ÁM. Tetrel Interactions from an Interacting Quantum Atoms Perspective. Molecules 2019; 24:E2204. [PMID: 31212835 DOI: 10.3390/molecules24122204] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 06/05/2019] [Accepted: 06/07/2019] [Indexed: 02/06/2023] Open
Abstract
Tetrel bonds, the purportedly non-covalent interaction between a molecule that contains an atom of group 14 and an anion or (more generally) an atom or molecule with lone electron pairs, are under intense scrutiny. In this work, we perform an interacting quantum atoms (IQA) analysis of several simple complexes formed between an electrophilic fragment (A) (CH3F, CH4, CO2, CS2, SiO2, SiH3F, SiH4, GeH3F, GeO2, and GeH4) and an electron-pair-rich system (B) (NCH, NCO-, OCN-, F-, Br-, CN-, CO, CS, Kr, NC-, NH3, OC, OH2, SH-, and N3-) at the aug-cc-pvtz coupled cluster singles and doubles (CCSD) level of calculation. The binding energy ( E bind AB ) is separated into intrafragment and inter-fragment components, and the latter in turn split into classical and covalent contributions. It is shown that the three terms are important in determining E bind AB , with absolute values that increase in passing from electrophilic fragments containing C, Ge, and Si. The degree of covalency between A and B is measured through the real space bond order known as the delocalization index ( δ AB ). Finally, a good linear correlation is found between δ AB and E xc AB , the exchange correlation (xc) or covalent contribution to E bind AB .
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Straßer C, Ludbrook BM, Levy G, Macdonald AJ, Burke SA, Wehling TO, Kern K, Damascelli A, Ast CR. Long- versus Short-Range Scattering in Doped Epitaxial Graphene. Nano Lett 2015; 15:2825-2829. [PMID: 25822076 DOI: 10.1021/nl504155f] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Tuning the electronic properties of graphene by adatom deposition unavoidably introduces disorder into the system, which directly affects the single-particle excitations and electrodynamics. Using angle-resolved photoemission spectroscopy (ARPES) we trace the evolution of disorder in graphene by thallium adatom deposition and probe its effect on the electronic structure. We show that the signatures of quasiparticle scattering in the photoemission spectral function can be used to identify thallium adatoms, although charged, as efficient short-range scattering centers. Employing a self-energy model for short-range scattering, we are able to extract a δ-like scattering potential δ = -3.2 ± 1 eV. Therefore, isolated charged scattering centers do not necessarily act just as good long-range (Coulomb) scatterers but can also act as efficient short-range (δ-like) scatterers; in the case of thallium, this happens with almost equal contributions from both mechanisms.
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Affiliation(s)
- C Straßer
- †Max Planck Institute for Solid State Research, 70569 Stuttgart, Germany
| | - B M Ludbrook
- §Quantum Matter Institute, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - G Levy
- §Quantum Matter Institute, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - A J Macdonald
- §Quantum Matter Institute, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - S A Burke
- §Quantum Matter Institute, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
- ∥Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - T O Wehling
- ⊥Institut für Theoretische Physik, Universität Bremen, 28359 Bremen, Germany
| | - K Kern
- †Max Planck Institute for Solid State Research, 70569 Stuttgart, Germany
- #Institut de Physique de la Matière Condensée, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - A Damascelli
- §Quantum Matter Institute, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - C R Ast
- †Max Planck Institute for Solid State Research, 70569 Stuttgart, Germany
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