1
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Mushkaev R, Petocchi F, Christiansson V, Werner P. Internal consistency of multi-tier G W+EDMFT. NPJ COMPUTATIONAL MATERIALS 2024; 10:182. [PMID: 39155927 PMCID: PMC11324523 DOI: 10.1038/s41524-024-01376-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Accepted: 07/29/2024] [Indexed: 08/20/2024]
Abstract
The multi-tier G W+EDMFT scheme is an ab-initio method for calculating the electronic structure of correlated materials. While the approach is free from ad-hoc parameters, it requires a selection of appropriate energy windows for describing low-energy and strongly correlated physics. In this study, we test the consistency of the multi-tier description by considering different low-energy windows for a series of cubic SrXO3 (X = V, Cr, Mn) perovskites. Specifically, we compare the 3-orbital t 2g model, the 5-orbital t 2g + e g model, the 12-orbital t 2g + O p model, and (in the case of SrVO3) the 14-orbital t 2g + e g + O p model and compare the results to available photoemission and X-ray absorption measurements. The multi-tier method yields consistent results for the t 2g and t 2g + e g low-energy windows, while the models with O p states produce stronger correlation effects and mostly agree well with experiment, especially in the unoccupied part of the spectrum. We also discuss the consistency between the fermionic and bosonic spectral functions and the physical origin of satellite features, and present momentum-resolved charge susceptibilities.
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Affiliation(s)
- Ruslan Mushkaev
- Department of Physics, University of Fribourg, 1700 Fribourg, Switzerland
| | - Francesco Petocchi
- Department of Quantum Matter Physics, University of Geneva, Geneva 4, Switzerland
| | | | - Philipp Werner
- Department of Physics, University of Fribourg, 1700 Fribourg, Switzerland
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2
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Harsha G, Abraham V, Zgid D. Challenges with relativistic GW calculations in solids and molecules. Faraday Discuss 2024. [PMID: 39101408 DOI: 10.1039/d4fd00043a] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/06/2024]
Abstract
For molecules and solids containing heavy elements, accurate electronic-structure calculations require accounting not only for electronic correlations but also for relativistic effects. In molecules, relativity can lead to severe changes in the ground-state description. In solids, the interplay between both correlation and relativity can change the stability of phases or it can lead to an emergence of completely new phases. Traditionally, the simplest illustration of relativistic effects can be done either by including pseudopotentials in non-relativistic calculations or alternatively by employing large all-electron basis sets in relativistic methods. By analyzing different electronic properties (band structure, equilibrium lattice constant and bulk modulus) in semiconductors and insulators, we show that capturing the interplay of relativity and electron correlation can be rather challenging in Green's function methods. For molecular problems with heavy elements, we also observe that similar problems persist. We trace these challenges to three major problems: deficiencies in pseudopotential treatment as applied to Green's function methods, the scarcity of accurate and compact all-electron basis sets that can be converged with respect to the basis-set size, and linear dependencies arising in all-electron basis sets, particularly when employing Gaussian orbitals. Our analysis provides detailed insight into these problems and opens a discussion about potential approaches to mitigate them.
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Affiliation(s)
- Gaurav Harsha
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, USA.
| | - Vibin Abraham
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, USA.
| | - Dominika Zgid
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, USA.
- Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, USA
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3
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Li J, Zhu T. Restoring translational symmetry in periodic all-orbital dynamical mean-field theory simulations. Faraday Discuss 2024. [PMID: 39076013 DOI: 10.1039/d4fd00068d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/31/2024]
Abstract
Dynamical mean-field theory (DMFT) and its cluster extensions provide an efficient Green's function formalism to simulate spectral properties of periodic systems at the quantum many-body level. However, traditional cluster DMFT breaks translational invariance in solid-state materials, and the best strategy to capture non-local correlation effects within cluster DMFT remains elusive. In this work, we investigate the use of overlapping atom-centered impurity fragments in recently-developed ab initio all-orbital DMFT, where all local orbitals within the impurity are treated with high-level quantum chemistry impurity solvers. We demonstrate how the translational symmetry of the lattice self-energy can be restored by designing symmetry-adapted embedding problems, which results in an improved description of spectral functions in two-dimensional boron nitride monolayers and graphene at the levels of many-body perturbation theory (GW) and coupled-cluster theory. Furthermore, we study the convergence of self-energy and density of states as the embedding size is systematically expanded in one-shot and self-consistent DMFT calculations.
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Affiliation(s)
- Jiachen Li
- Department of Chemistry, Yale University, New Haven, CT, 06520, USA.
| | - Tianyu Zhu
- Department of Chemistry, Yale University, New Haven, CT, 06520, USA.
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4
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Kang B, Kim M, Park CH, Janotti A. Mott-Insulator State of FeSe as a Van der Waals 2D Material Is Unveiled. PHYSICAL REVIEW LETTERS 2024; 132:266506. [PMID: 38996314 DOI: 10.1103/physrevlett.132.266506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Revised: 04/25/2024] [Accepted: 05/28/2024] [Indexed: 07/14/2024]
Abstract
We undertook a comprehensive investigation of the electronic structure of FeSe, known as a Hund metal, and found that it is not uniquely defined. Through accounting for all two-particle irreducible diagrams constructed from electron Green's function G and screened Coulomb interaction W in a self-consistent manner, a Mott-insulator phase of 2D-FeSe is unveiled. The metal-insulator transition is driven by the strong on-site Coulomb interaction in its paramagnetic phase, accompanied by the weakening of both local and nonlocal screening effects on the Fe-3d orbitals. Our results suggest that Mott physics may play a pivotal role in shaping the electronic, optical, and superconducting properties of monolayer or nanostructured FeSe.
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5
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Chatzieleftheriou M, Biermann S, Stepanov EA. Local and Nonlocal Electronic Correlations at the Metal-Insulator Transition in the Two-Dimensional Hubbard Model. PHYSICAL REVIEW LETTERS 2024; 132:236504. [PMID: 38905678 DOI: 10.1103/physrevlett.132.236504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Accepted: 05/13/2024] [Indexed: 06/23/2024]
Abstract
Elucidating the physics of the single-orbital Hubbard model in its intermediate-coupling regime is a key missing ingredient to our understanding of metal-insulator transitions in real materials. Using recent nonperturbative many-body techniques that are able to interpolate between the spin-fluctuation-dominated Slater regime at weak coupling and the Mott insulator at strong coupling, we obtain the momentum-resolved spectral function in the intermediate regime and disentangle the effects of antiferromagnetic fluctuations and local electronic correlations in the formation of an insulating state. This allows us to identify the Slater and Heisenberg regimes in the phase diagram, which are separated by a crossover region of competing spatial and local electronic correlations. We identify the crossover regime by investigating the behavior of the local magnetic moment, shedding light on the formation of the insulating state at intermediate couplings.
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Affiliation(s)
| | - Silke Biermann
- CPHT, CNRS, École polytechnique, Institut Polytechnique de Paris, 91120 Palaiseau, France
- Collège de France, 11 place Marcelin Berthelot, 75005 Paris, France
- European Theoretical Spectroscopy Facility, 91128 Palaiseau, France
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6
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Gao W, Tang Z, Zhao J, Chelikowsky JR. Efficient Full-Frequency GW Calculations Using a Lanczos Method. PHYSICAL REVIEW LETTERS 2024; 132:126402. [PMID: 38579203 DOI: 10.1103/physrevlett.132.126402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Accepted: 02/21/2024] [Indexed: 04/07/2024]
Abstract
The GW approximation is widely used for reliable and accurate modeling of single-particle excitations. It also serves as a starting point for many theoretical methods, such as its use in the Bethe-Salpeter equation (BSE) and dynamical mean-field theory. However, full-frequency GW calculations for large systems with hundreds of atoms remain computationally challenging, even after years of efforts to reduce the prefactor and improve scaling. We propose a method that reformulates the correlation part of the GW self-energy as a resolvent of a Hermitian matrix, which can be efficiently and accurately computed using the standard Lanczos method. This method enables full-frequency GW calculations of material systems with a few hundred atoms on a single computing workstation. We further demonstrate the efficiency of the method by calculating the defect-state energies of silicon quantum dots with diameters up to 4 nm and nearly 2,000 silicon atoms using only 20 computational nodes.
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Affiliation(s)
- Weiwei Gao
- Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, Ministry of Education, Dalian University of Technology, Dalian 116024, China
| | - Zhao Tang
- Center for Computational Materials, Oden Institute for Computational Engineering and Sciences, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Jijun Zhao
- Key Laboratory of Atomic and Subatomic Structure and Quantum Control (Ministry of Education), Guangdong Basic Research Center of Excellence for Structure and Fundamental Interactions of Matter, School of Physics, South China Normal University, Guangzhou 510006, China
| | - James R Chelikowsky
- Center for Computational Materials, Oden Institute for Computational Engineering and Sciences, The University of Texas at Austin, Austin, Texas 78712, USA
- Department of Physics, The University of Texas at Austin, Austin, Texas 78712, USA
- McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, Texas 78712, USA
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7
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Christiansson V, Petocchi F, Werner P. Correlated Electronic Structure of La_{3}Ni_{2}O_{7} under Pressure. PHYSICAL REVIEW LETTERS 2023; 131:206501. [PMID: 38039471 DOI: 10.1103/physrevlett.131.206501] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 08/25/2023] [Accepted: 09/27/2023] [Indexed: 12/03/2023]
Abstract
Recently, superconductivity with a T_{c} up to 78 K has been reported in bulk samples of the bilayer nickelate La_{3}Ni_{2}O_{7} at pressures above 14 GPa. Important theoretical tasks are the formulation of relevant low-energy models and the clarification of the normal state properties. Here, we study the correlated electronic structure of the high-pressure phase in a four-orbital low-energy subspace using different many-body approaches: GW, dynamical mean field theory (DMFT), extended DMFT (EDMFT) and GW+EDMFT, with realistic frequency-dependent interaction parameters. The nonlocal correlation and screening effects captured by GW+EDMFT result in an instability toward the formation of charge stripes, with the 3d_{z^{2}} as the main active orbital. We also comment on the potential relevance of the rare-earth self-doping pocket, since hole doping suppresses the ordering tendency.
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Affiliation(s)
| | - Francesco Petocchi
- Department of Quantum Matter Physics, University of Geneva, 1211 Geneva 4, Switzerland
| | - Philipp Werner
- Department of Physics, University of Fribourg, 1700 Fribourg, Switzerland
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8
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van Loon EGCP, Schüler M, Springer D, Sangiovanni G, Tomczak JM, Wehling TO. Coulomb engineering of two-dimensional Mott materials. NPJ 2D MATERIALS AND APPLICATIONS 2023; 7:47. [PMID: 38665482 PMCID: PMC11041779 DOI: 10.1038/s41699-023-00408-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Accepted: 06/15/2023] [Indexed: 04/28/2024]
Abstract
Two-dimensional materials can be strongly influenced by their surroundings. A dielectric environment screens and reduces the Coulomb interaction between electrons in the two-dimensional material. Since in Mott materials the Coulomb interaction is responsible for the insulating state, manipulating the dielectric screening provides direct control over Mottness. Our many-body calculations reveal the spectroscopic fingerprints of such Coulomb engineering: we demonstrate eV-scale changes to the position of the Hubbard bands and show a Coulomb engineered insulator-to-metal transition. Based on our proof-of-principle calculations, we discuss the (feasible) conditions under which our scenario of Coulomb engineering of Mott materials can be realized experimentally.
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Affiliation(s)
- Erik G. C. P. van Loon
- Mathematical Physics Division, Department of Physics, Lund University, Lund, Sweden
- Institut für Theoretische Physik, Universität Bremen, Otto-Hahn-Allee 1, 28359 Bremen, Germany
- Bremen Center for Computational Materials Science, Universität Bremen, Am Fallturm 1a, 28359 Bremen, Germany
| | - Malte Schüler
- Institut für Theoretische Physik, Universität Bremen, Otto-Hahn-Allee 1, 28359 Bremen, Germany
- Bremen Center for Computational Materials Science, Universität Bremen, Am Fallturm 1a, 28359 Bremen, Germany
| | - Daniel Springer
- Institute of Solid State Physics, TU Wien, A-1040 Vienna, Austria
- Institute of Advanced Research in Artificial Intelligence, IARAI, A-1030 Vienna, Austria
| | - Giorgio Sangiovanni
- Institut für Theoretische Physik und Astrophysik and Würzburg-Dresden Cluster of Excellence ct.qmat, Universität Würzburg, 97074 Würzburg, Germany
| | - Jan M. Tomczak
- Institute of Solid State Physics, TU Wien, A-1040 Vienna, Austria
- Department of Physics, King’s College London, Strand, London, WC2R 2LS UK
| | - Tim O. Wehling
- I. Institute of Theoretical Physics, University of Hamburg, D-22607 Hamburg, Germany
- The Hamburg Centre for Ultrafast Imaging, D-22761 Hamburg, Germany
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9
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Kim TJ, Jeong MY, Han MJ. First principles investigation of screened Coulomb interaction and electronic structure of low-temperature phase TaS 2. iScience 2023; 26:106681. [PMID: 37250339 PMCID: PMC10214477 DOI: 10.1016/j.isci.2023.106681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 03/28/2023] [Accepted: 04/12/2023] [Indexed: 05/31/2023] Open
Abstract
By means of ab initio computation schemes, we examine the electronic screening, Coulomb interaction strength, and the electronic structure of a quantum spin liquid candidate monolayer TaS2 in its low-temperature commensurate charge-density-wave phase. Not only local (U) but non-local (V) correlations are estimated within random phase approximation based on two different screening models. Using GW + EDMFT (GW plus extended dynamical mean-field theory) method, we investigate the detailed electronic structure by increasing the level of non-local approximation from DMFT (V=0) to EDMFT and GW + EDMFT.
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Affiliation(s)
- Taek Jung Kim
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
| | - Min Yong Jeong
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
| | - Myung Joon Han
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
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10
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Liu Y, Meitei OR, Chin ZE, Dutt A, Tao M, Chuang IL, Van Voorhis T. Bootstrap Embedding on a Quantum Computer. J Chem Theory Comput 2023; 19:2230-2247. [PMID: 37001026 DOI: 10.1021/acs.jctc.3c00012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2023]
Abstract
We extend molecular bootstrap embedding to make it appropriate for implementation on a quantum computer. This enables solution of the electronic structure problem of a large molecule as an optimization problem for a composite Lagrangian governing fragments of the total system, in such a way that fragment solutions can harness the capabilities of quantum computers. By employing state-of-art quantum subroutines including the quantum SWAP test and quantum amplitude amplification, we show how a quadratic speedup can be obtained over the classical algorithm, in principle. Utilization of quantum computation also allows the algorithm to match─at little additional computational cost─full density matrices at fragment boundaries, instead of being limited to 1-RDMs. Current quantum computers are small, but quantum bootstrap embedding provides a potentially generalizable strategy for harnessing such small machines through quantum fragment matching.
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Affiliation(s)
- Yuan Liu
- Department of Physics, Co-Design Center for Quantum Advantage, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Oinam R. Meitei
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Zachary E. Chin
- Department of Physics, Co-Design Center for Quantum Advantage, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Arkopal Dutt
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Max Tao
- Department of Physics, Co-Design Center for Quantum Advantage, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Isaac L. Chuang
- Department of Physics, Co-Design Center for Quantum Advantage, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Troy Van Voorhis
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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11
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Siddiquee H, Broyles C, Kotta E, Liu S, Peng S, Kong T, Kang B, Zhu Q, Lee Y, Ke L, Weng H, Denlinger JD, Wray LA, Ran S. Breakdown of the scaling relation of anomalous Hall effect in Kondo lattice ferromagnet USbTe. Nat Commun 2023; 14:527. [PMID: 36720874 PMCID: PMC9889341 DOI: 10.1038/s41467-023-36221-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Accepted: 01/18/2023] [Indexed: 02/02/2023] Open
Abstract
The interaction between strong correlation and Berry curvature is an open territory of in the field of quantum materials. Here we report large anomalous Hall conductivity in a Kondo lattice ferromagnet USbTe which is dominated by intrinsic Berry curvature at low temperatures. However, the Berry curvature induced anomalous Hall effect does not follow the scaling relation derived from Fermi liquid theory. The onset of the Berry curvature contribution coincides with the Kondo coherent temperature. Combined with ARPES measurement and DMFT calculations, this strongly indicates that Berry curvature is hosted by the flat bands induced by Kondo hybridization at the Fermi level. Our results demonstrate that the Kondo coherence of the flat bands has a dramatic influence on the low temperature physical properties associated with the Berry curvature, calling for new theories of scaling relations of anomalous Hall effect to account for the interaction between strong correlation and Berry curvature.
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Affiliation(s)
- Hasan Siddiquee
- Department of Physics, Washington University in St. Louis, St. Louis, MO, 63130, USA
| | - Christopher Broyles
- Department of Physics, Washington University in St. Louis, St. Louis, MO, 63130, USA
| | - Erica Kotta
- Department of Physics, New York University, New York, NY, 10003, USA
| | - Shouzheng Liu
- Department of Physics, New York University, New York, NY, 10003, USA
| | - Shiyu Peng
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Tai Kong
- Department of Physics, University of Arizona, Tucson, AZ, 85721, USA
| | | | - Qiang Zhu
- University of Nevada, Las Vegas, NV, 89154, USA
| | | | | | - Hongming Weng
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Jonathan D Denlinger
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - L Andrew Wray
- Department of Physics, New York University, New York, NY, 10003, USA
| | - Sheng Ran
- Department of Physics, Washington University in St. Louis, St. Louis, MO, 63130, USA.
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12
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Vorwerk C, Sheng N, Govoni M, Huang B, Galli G. Quantum embedding theories to simulate condensed systems on quantum computers. NATURE COMPUTATIONAL SCIENCE 2022; 2:424-432. [PMID: 38177872 DOI: 10.1038/s43588-022-00279-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 06/14/2022] [Indexed: 01/06/2024]
Abstract
Quantum computers hold promise to improve the efficiency of quantum simulations of materials and to enable the investigation of systems and properties that are more complex than tractable at present on classical architectures. Here, we discuss computational frameworks to carry out electronic structure calculations of solids on noisy intermediate-scale quantum computers using embedding theories, and we give examples for a specific class of materials, that is, solid materials hosting spin defects. These are promising systems to build future quantum technologies, such as quantum computers, quantum sensors and quantum communication devices. Although quantum simulations on quantum architectures are in their infancy, promising results for realistic systems appear to be within reach.
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Affiliation(s)
- Christian Vorwerk
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL, USA
| | - Nan Sheng
- Department of Chemistry, University of Chicago, Chicago, IL, USA
| | - Marco Govoni
- Materials Science Division and Center for Molecular Engineering, Argonne National Laboratory, Lemont, IL, USA.
| | - Benchen Huang
- Department of Chemistry, University of Chicago, Chicago, IL, USA
| | - Giulia Galli
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL, USA.
- Department of Chemistry, University of Chicago, Chicago, IL, USA.
- Materials Science Division and Center for Molecular Engineering, Argonne National Laboratory, Lemont, IL, USA.
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13
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Petocchi F, Nicholson CW, Salzmann B, Pasquier D, Yazyev OV, Monney C, Werner P. Mott versus Hybridization Gap in the Low-Temperature Phase of 1T-TaS_{2}. PHYSICAL REVIEW LETTERS 2022; 129:016402. [PMID: 35841569 DOI: 10.1103/physrevlett.129.016402] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Revised: 04/07/2022] [Accepted: 06/01/2022] [Indexed: 06/15/2023]
Abstract
We address the long-standing problem of the ground state of 1T-TaS_{2} by computing the correlated electronic structure of stacked bilayers using the GW+EDMFT method. Depending on the surface termination, the semi-infinite uncorrelated system is either band insulating or exhibits a metallic surface state. For realistic values of the on-site and inter-site interactions, a Mott gap opens in the surface state, but it is smaller than the gap originating from the bilayer structure. Our results are consistent with recent scanning tunneling spectroscopy measurements for different terminating layers, and with our own photoemission measurements, which indicate the coexistence of spatial regions with different gaps in the electronic spectrum. By comparison to exact diagonalization data, we clarify the interplay between Mott insulating and band insulating behavior in this archetypal layered system.
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Affiliation(s)
- Francesco Petocchi
- Department of Physics, University of Fribourg, 1700 Fribourg, Switzerland
| | - Christopher W Nicholson
- Department of Physics, University of Fribourg, 1700 Fribourg, Switzerland
- Fritz-Haber-Institute der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
| | - Bjoern Salzmann
- Department of Physics, University of Fribourg, 1700 Fribourg, Switzerland
| | - Diego Pasquier
- Institute of Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Oleg V Yazyev
- Institute of Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Claude Monney
- Department of Physics, University of Fribourg, 1700 Fribourg, Switzerland
| | - Philipp Werner
- Department of Physics, University of Fribourg, 1700 Fribourg, Switzerland
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14
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Cho Y, Bintrim SJ, Berkelbach TC. Simplified GW/BSE Approach for Charged and Neutral Excitation Energies of Large Molecules and Nanomaterials. J Chem Theory Comput 2022; 18:3438-3446. [PMID: 35544591 DOI: 10.1021/acs.jctc.2c00087] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Inspired by Grimme's simplified Tamm-Dancoff density functional theory approach [Grimme, S. J. Chem. Phys. 2013, 138, 244104], we describe a simplified approach to excited-state calculations within the GW approximation to the self-energy and the Bethe-Salpeter equation (BSE), which we call sGW/sBSE. The primary simplification to the electron repulsion integrals yields the same structure as with tensor hypercontraction, such that our method has a storage requirement that grows quadratically with system size and computational timing that grows cubically with system size. The performance of sGW is tested on the ionization potential of the molecules in the GW100 test set, for which it differs from ab initio GW calculations by only 0.2 eV. The performance of sBSE (based on the sGW input) is tested on the excitation energies of molecules in Thiel's set, for which it differs from ab initio GW/BSE calculations by about 0.5 eV. As examples of the systems that can be routinely studied with sGW/sBSE, we calculate the band gap and excitation energy of hydrogen-passivated silicon nanocrystals with up to 2650 electrons in 4678 spatial orbitals and the absorption spectra of two large organic dye molecules with hundreds of atoms.
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Affiliation(s)
- Yeongsu Cho
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Sylvia J Bintrim
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Timothy C Berkelbach
- Department of Chemistry, Columbia University, New York, New York 10027, United States.,Center for Computational Quantum Physics, Flatiron Institute, New York, New York 10010, United States
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15
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Krien F, Kauch A. The plain and simple parquet approximation: single-and multi-boson exchange in the two-dimensional Hubbard model. THE EUROPEAN PHYSICAL JOURNAL. B 2022; 95:69. [PMID: 35531566 PMCID: PMC9023420 DOI: 10.1140/epjb/s10051-022-00329-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 04/01/2022] [Indexed: 06/14/2023]
Abstract
Abstract The parquet approach to vertex corrections is unbiased but computationally demanding. Most applications are therefore restricted to small cluster sizes or rely on various simplifying approximations. We have recently shown that the bosonization of the parquet diagrams provides interpretative and algorithmic advantages over the original purely fermionic formulation. Here, we present first results of the numerical implementation of this method by applying it to the half-filled Hubbard model on the square lattice at weak coupling. The improved algorithmic performance allows us to evaluate the parquet approximation for a 16 × 16 lattice, retaining the full momentum and frequency structure of the various vertex functions. We discuss their symmetries and consider parametrizations of their momentum dependence using the truncated-unity approximation. Graphical abstract
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Affiliation(s)
- Friedrich Krien
- Institute of Solid State Physics, TU Wien, 1040 Vienna, Austria
| | - Anna Kauch
- Institute of Solid State Physics, TU Wien, 1040 Vienna, Austria
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16
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Shee A, Yeh CN, Zgid D. Exploring Coupled Cluster Green's Function as a Method for Treating System and Environment in Green's Function Embedding Methods. J Chem Theory Comput 2022; 18:664-676. [PMID: 34989565 DOI: 10.1021/acs.jctc.1c00712] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Within the self-energy embedding theory (SEET) framework, we study the coupled cluster Green's function (GFCC) method in two different contexts: as a method to treat either the system or the environment present in the embedding construction. Our study reveals that when GFCC is used to treat the environment we do not see improvement in total energies in comparison to the coupled cluster method itself. To rationalize this puzzling result, we analyze the performance of GFCC as an impurity solver with a series of transition metal oxides. These studies shed light on the strength and weaknesses of such a solver and demonstrate that such a solver gives very accurate results when the size of the impurity is small. We investigate if it is possible to achieve a systematic accuracy of the embedding solution when we increase the size of the impurity problem. We found that in such a case, the performance of the solver worsens, both in terms of finding the ground state solution of the impurity problem and the self-energies produced. We concluded that increasing the rank of GFCC solver is necessary to be able to enlarge impurity problems and achieve a reliable accuracy. We also have shown that natural orbitals from weakly correlated perturbative methods are better suited than symmetrized atomic orbitals (SAO) when the total energy of the system is the target quantity.
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Affiliation(s)
- Avijit Shee
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Chia-Nan Yeh
- Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Dominika Zgid
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
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17
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Ahn C, Cavalleri A, Georges A, Ismail-Beigi S, Millis AJ, Triscone JM. Designing and controlling the properties of transition metal oxide quantum materials. NATURE MATERIALS 2021; 20:1462-1468. [PMID: 33941911 DOI: 10.1038/s41563-021-00989-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 03/17/2021] [Indexed: 06/12/2023]
Abstract
This Perspective addresses the design, creation, characterization and control of synthetic quantum materials with strong electronic correlations. We show how emerging synergies between theoretical/computational approaches and materials design/experimental probes are driving recent advances in the discovery, understanding and control of new electronic behaviour in materials systems with interesting and potentially technologically important properties. The focus here is on transition metal oxides, where electronic correlations lead to a myriad of functional properties including superconductivity, magnetism, Mott transitions, multiferroicity and emergent behaviour at picoscale-designed interfaces. Current opportunities and challenges are also addressed, including possible new discoveries of non-equilibrium phenomena and optical control of correlated quantum phases of transition metal oxides.
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Affiliation(s)
| | - Andrea Cavalleri
- Max Planck Institute for the Structure and Dynamics of Matter, Hamburg, Germany
| | - Antoine Georges
- Collège de France, Paris, France
- CCQ-Flatiron Institute, New York, NY, USA
| | | | - Andrew J Millis
- CCQ-Flatiron Institute, New York, NY, USA
- Columbia University, New York, NY, USA
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18
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Kutepov AL. Spatial non-locality of electronic correlations beyond GW approximation. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:485601. [PMID: 34488212 DOI: 10.1088/1361-648x/ac23fa] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 09/06/2021] [Indexed: 06/13/2023]
Abstract
The question of spatial locality of electronic correlations beyond GW approximation is one of the central issues of the famous combination of GW and dynamical mean field theory, GW + DMFT. In this work, the above question is addressed directly (for the first time) by performing calculations with and without assumption of locality of the corresponding diagrams. For this purpose we use sc(GW + G3W2) approach where the higher order part (G3W2) is evaluated with fully momentum dependent Green's function G and screened interaction W and with 'local' variant, where the single site approximation is assumed for both G and W. For all three materials studied in this work (NiO,α-Ce, LiFeAs), we have found the spatial non-locality effects to be strong. For NiO and LiFeAs they, in fact, are decisive for the proper evaluation of vertex corrections. The results of this study have direct impact on our understanding of approximations made in practical implementations of GW + DMFT method, where all diagrams beyond GW (DMFT part) are assumed to be local. Taking into account the fact that the first diagrams beyond GW represent the most important contribution also in GW + DMFT calculations, we conclude that the basic assumption of GW + DMFT, namely the locality of diagrams evaluated in the DMFT part, is not as good as it is believed to be.
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Affiliation(s)
- A L Kutepov
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, NY 11973, United States of America
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19
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Requist R, Gross EKU. Fock-Space Embedding Theory: Application to Strongly Correlated Topological Phases. PHYSICAL REVIEW LETTERS 2021; 127:116401. [PMID: 34558918 DOI: 10.1103/physrevlett.127.116401] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Accepted: 07/15/2021] [Indexed: 06/13/2023]
Abstract
A many-body wave function can be factorized in Fock space into a marginal amplitude describing a set of strongly correlated orbitals and a conditional amplitude for the remaining weakly correlated part. The marginal amplitude is the solution of a Schrödinger equation with an effective Hamiltonian that can be viewed as embedding the marginal wave function in the environment of weakly correlated electrons. Here, the complementary equation for the conditional amplitude is replaced by a generalized Kohn-Sham equation, for which an orbital-dependent functional approximation is shown to reproduce the topological phase diagram of a multiband Hubbard model as a function of crystal field and Hubbard parameters. The roles of band filling and interband fluctuations are elucidated.
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Affiliation(s)
- Ryan Requist
- Max Planck Institute of Microstructure Physics, Weinberg 2, 06120 Halle, Germany and Fritz Haber Center for Molecular Dynamics, Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - E K U Gross
- Max Planck Institute of Microstructure Physics, Weinberg 2, 06120 Halle, Germany and Fritz Haber Center for Molecular Dynamics, Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
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20
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Karlsson D, van Leeuwen R, Pavlyukh Y, Perfetto E, Stefanucci G. Fast Green's Function Method for Ultrafast Electron-Boson Dynamics. PHYSICAL REVIEW LETTERS 2021; 127:036402. [PMID: 34328754 DOI: 10.1103/physrevlett.127.036402] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 03/29/2021] [Accepted: 05/20/2021] [Indexed: 06/13/2023]
Abstract
The interaction of electrons with quantized phonons and photons underlies the ultrafast dynamics of systems ranging from molecules to solids, and it gives rise to a plethora of physical phenomena experimentally accessible using time-resolved techniques. Green's function methods offer an invaluable interpretation tool since scattering mechanisms of growing complexity can be selectively incorporated in the theory. Currently, however, real-time Green's function simulations are either prohibitively expensive due to the cubic scaling with the propagation time or do neglect the feedback of electrons on the bosons, thus violating energy conservation. We put forward a computationally efficient Green's function scheme which overcomes both limitations. The numerical effort scales linearly with the propagation time while the simultaneous dressing of electrons and bosons guarantees the fulfillment of all fundamental conservation laws. We present a real-time study of the phonon-driven relaxation dynamics in an optically excited narrow band-gap insulator, highlighting the nonthermal behavior of the phononic degrees of freedom. Our formulation paves the way to first-principles simulations of electron-boson systems with unprecedented long propagation times.
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Affiliation(s)
- Daniel Karlsson
- Department of Physics, Nanoscience Center, University of Jyväskylä, P.O. Box 35, FI-40014 Jyväskylä, Finland
| | - Robert van Leeuwen
- Department of Physics, Nanoscience Center, University of Jyväskylä, P.O. Box 35, FI-40014 Jyväskylä, Finland
| | - Yaroslav Pavlyukh
- Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, 06120 Halle, Germany
- Dipartimento di Fisica, Università di Roma Tor Vergata, Via della Ricerca Scientifica 1, 00133 Rome, Italy
| | - Enrico Perfetto
- Dipartimento di Fisica, Università di Roma Tor Vergata, Via della Ricerca Scientifica 1, 00133 Rome, Italy
- INFN, Sezione di Roma Tor Vergata, Via della Ricerca Scientifica 1, 00133 Rome, Italy
| | - Gianluca Stefanucci
- Dipartimento di Fisica, Università di Roma Tor Vergata, Via della Ricerca Scientifica 1, 00133 Rome, Italy
- INFN, Sezione di Roma Tor Vergata, Via della Ricerca Scientifica 1, 00133 Rome, Italy
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21
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Marzari N, Ferretti A, Wolverton C. Electronic-structure methods for materials design. NATURE MATERIALS 2021; 20:736-749. [PMID: 34045704 DOI: 10.1038/s41563-021-01013-3] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Accepted: 04/19/2021] [Indexed: 05/24/2023]
Abstract
The accuracy and efficiency of electronic-structure methods to understand, predict and design the properties of materials has driven a new paradigm in research. Simulations can greatly accelerate the identification, characterization and optimization of materials, with this acceleration driven by continuous progress in theory, algorithms and hardware, and by adaptation of concepts and tools from computer science. Nevertheless, the capability to identify and characterize materials relies on the predictive accuracy of the underlying physical descriptions, and on the ability to capture the complexity of realistic systems. We provide here an overview of electronic-structure methods, of their application to the prediction of materials properties, and of the different strategies employed towards the broader goals of materials design and discovery.
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Affiliation(s)
- Nicola Marzari
- Theory and Simulation of Materials (THEOS), and National Centre for Computational Design and Discovery of Novel Materials (MARVEL), École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
| | | | - Chris Wolverton
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL, USA
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22
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Advanced First-Principle Modeling of Relativistic Ruddlesden—Popper Strontium Iridates. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11062527] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
In this review, we provide a survey of the application of advanced first-principle methods on the theoretical modeling and understanding of novel electronic, optical, and magnetic properties of the spin-orbit coupled Ruddlesden–Popper series of iridates Srn+1IrnO3n+1 (n = 1, 2, and ∞). After a brief description of the basic aspects of the adopted methods (noncollinear local spin density approximation plus an on-site Coulomb interaction (LSDA+U), constrained random phase approximation (cRPA), GW, and Bethe–Salpeter equation (BSE)), we present and discuss select results. We show that a detailed phase diagrams of the metal–insulator transition and magnetic phase transition can be constructed by inspecting the evolution of electronic and magnetic properties as a function of Hubbard U, spin–orbit coupling (SOC) strength, and dimensionality n, which provide clear evidence for the crucial role played by SOC and U in establishing a relativistic (Dirac) Mott–Hubbard insulating state in Sr2IrO4 and Sr3Ir2O7. To characterize the ground-state phases, we quantify the most relevant energy scales fully ab initio—crystal field energy, Hubbard U, and SOC constant of three compounds—and discuss the quasiparticle band structures in detail by comparing GW and LSDA+U data. We examine the different magnetic ground states of structurally similar n = 1 and n = 2 compounds and clarify that the origin of the in-plane canted antiferromagnetic (AFM) state of Sr2IrO4 arises from competition between isotropic exchange and Dzyaloshinskii–Moriya (DM) interactions whereas the collinear AFM state of Sr3Ir2O7 is due to strong interlayer magnetic coupling. Finally, we report the dimensionality controlled metal–insulator transition across the series by computing their optical transitions and conductivity spectra at the GW+BSE level from the the quasi two-dimensional insulating n = 1 and 2 phases to the three-dimensional metallic n=∞ phase.
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23
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Jacob D, Stefanucci G, Kurth S. Mott Metal-Insulator Transition from Steady-State Density Functional Theory. PHYSICAL REVIEW LETTERS 2020; 125:216401. [PMID: 33274971 DOI: 10.1103/physrevlett.125.216401] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Accepted: 10/15/2020] [Indexed: 06/12/2023]
Abstract
We present a computationally efficient method to obtain the spectral function of bulk systems in the framework of steady-state density functional theory (i-DFT) using an idealized scanning tunneling microscope (STM) setup. We calculate the current through the STM tip and then extract the spectral function from the finite-bias differential conductance. The fictitious noninteracting system of i-DFT features an exchange-correlation (XC) contribution to the bias which guarantees the same current as in the true interacting system. Exact properties of the XC bias are established using Fermi-liquid theory and subsequently implemented to construct approximations for the Hubbard model. We show for two different lattice structures that the Mott metal-insulator transition is captured by i-DFT.
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Affiliation(s)
- David Jacob
- Nano-Bio Spectroscopy Group and European Theoretical Spectroscopy Facility (ETSF), Departamento Polímeros y Materiales Avanzados: Física, Química y Tecnología, Universidad del País Vasco UPV/EHU, Avenida Tolosa 72, E-20018 San Sebastián, Spain
- IKERBASQUE, Basque Foundation for Science, Plaza Euskadi 5, E-48009 Bilbao, Spain
| | - Gianluca Stefanucci
- Dipartimento di Fisica, Università di Roma Tor Vergata, Via della Ricerca Scientifica 1, 00133 Rome, Italy
- INFN, Sezione di Roma Tor Vergata, Via della Ricerca Scientifica 1, 00133 Rome, Italy
| | - Stefan Kurth
- Nano-Bio Spectroscopy Group and European Theoretical Spectroscopy Facility (ETSF), Departamento Polímeros y Materiales Avanzados: Física, Química y Tecnología, Universidad del País Vasco UPV/EHU, Avenida Tolosa 72, E-20018 San Sebastián, Spain
- IKERBASQUE, Basque Foundation for Science, Plaza Euskadi 5, E-48009 Bilbao, Spain
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizabal 4, E-20018 San Sebastián, Spain
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24
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Eidelstein E, Gull E, Cohen G. Multiorbital Quantum Impurity Solver for General Interactions and Hybridizations. PHYSICAL REVIEW LETTERS 2020; 124:206405. [PMID: 32501050 DOI: 10.1103/physrevlett.124.206405] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 04/10/2020] [Accepted: 05/11/2020] [Indexed: 06/11/2023]
Abstract
We present a numerically exact inchworm Monte Carlo method for equilibrium multiorbital quantum impurity problems with general interactions and hybridizations. We show that the method, originally developed to overcome the dynamical sign problem in certain real-time propagation problems, can also overcome the sign problem as a function of temperature for equilibrium quantum impurity models. This is shown in several cases where the current method of choice, the continuous-time hybridization expansion, fails due to the sign problem. Our method therefore enables simulations of impurity problems as they appear in embedding theories without further approximations, such as the truncation of the hybridization or interaction structure or a discretization of the impurity bath with a set of discrete energy levels, and eliminates a crucial bottleneck in the simulation of ab initio embedding problems.
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Affiliation(s)
- Eitan Eidelstein
- Department of Physics, NRCN, P.O. Box 9001, Beer Sheva 84190, Israel
- School of Chemistry, Tel Aviv University, Tel Aviv 69978, Israel
| | - Emanuel Gull
- Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, USA
- Center for Computational Quantum Physics, Flatiron Institute, New York, New York 10010, USA
| | - Guy Cohen
- School of Chemistry, Tel Aviv University, Tel Aviv 69978, Israel
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25
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Wang X, Berkelbach TC. Excitons in Solids from Periodic Equation-of-Motion Coupled-Cluster Theory. J Chem Theory Comput 2020; 16:3095-3103. [DOI: 10.1021/acs.jctc.0c00101] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Xiao Wang
- Center for Computational Quantum Physics, Flatiron Institute, New York, New York 10010, United States
| | - Timothy C. Berkelbach
- Center for Computational Quantum Physics, Flatiron Institute, New York, New York 10010, United States
- Department of Chemistry, Columbia University, New York, New York 10027, United States
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26
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Zantout K, Backes S, Valentí R. Effect of Nonlocal Correlations on the Electronic Structure of LiFeAs. PHYSICAL REVIEW LETTERS 2019; 123:256401. [PMID: 31922793 DOI: 10.1103/physrevlett.123.256401] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Indexed: 06/10/2023]
Abstract
We investigate the role of nonlocal correlations in LiFeAs by exploring an ab initio-derived multiorbital Hubbard model for LiFeAs via the two-particle self-consistent (TPSC) approach. The multiorbital formulation of TPSC approximates the irreducible interaction vertex to be an orbital-dependent constant, which is self-consistently determined from local spin and charge sum rules. Within this approach, we disentangle the contribution of local and nonlocal correlations in LiFeAs and show that in the local approximation one recovers the dynamical mean field theory result. The comparison of our theoretical results to most recent angular-resolved photoemission spectroscopy and de Haas-van Alphen data shows that nonlocal correlations in LiFeAs are decisive to describe the measured spectral function A(k[over →],ω), Fermi surface, and scattering rates. These findings underline the importance of nonlocal correlations and benchmark different theoretical approaches for iron-based superconductors.
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Affiliation(s)
- Karim Zantout
- Institut für Theoretische Physik, Goethe-Universität Frankfurt, 60438 Frankfurt am Main, Germany
| | - Steffen Backes
- CPHT, CNRS, Institut Polytechnique de Paris, F-91128 Palaiseau, France
| | - Roser Valentí
- Institut für Theoretische Physik, Goethe-Universität Frankfurt, 60438 Frankfurt am Main, Germany
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27
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Zhu T, Cui ZH, Chan GKL. Efficient Formulation of Ab Initio Quantum Embedding in Periodic Systems: Dynamical Mean-Field Theory. J Chem Theory Comput 2019; 16:141-153. [DOI: 10.1021/acs.jctc.9b00934] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- Tianyu Zhu
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Zhi-Hao Cui
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Garnet Kin-Lic Chan
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
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28
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In 't Veld Y, Schüler M, Wehling TO, Katsnelson MI, van Loon EGCP. Bandwidth renormalization due to the intersite Coulomb interaction. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:465603. [PMID: 31362270 DOI: 10.1088/1361-648x/ab36fe] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The theory of correlated electrons is currently moving beyond the paradigmatic Hubbard U, towards the investigation of intersite Coulomb interactions. Recent investigations have revealed that these interactions are relevant for the quantitative description of realistic materials. Physically, intersite interactions are responsible for two rather different effects: screening and bandwidth renormalization. We use a variational principle to disentangle the roles of these two processes and study how appropriate the recently proposed Fock treatment of intersite interactions is in correlated systems. The magnitude of this effect in graphene is calculated based on cRPA values of the intersite interaction. We also apply the variational principle to benzene and find effective parameters comparable to those obtained by ab initio density matrix downfolding.
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Affiliation(s)
- Yann In 't Veld
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, NL-6525 AJ Nijmegen, The Netherlands
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29
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Yoon H, Jang SW, Sim JH, Kotani T, Han MJ. Magnetic force theory combined with quasi-particle self-consistent GW method. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:405503. [PMID: 31220821 DOI: 10.1088/1361-648x/ab2b7e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We report a successful combination of magnetic force linear response theory with quasiparticle self-consistent GW method. The self-consistently determined wavefunctions and eigenvalues can just be used for the conventional magnetic force calculations. While its formulation is straightforward, this combination provides a way to investigate the effect of GW self-energy on the magnetic interactions which can hardly be quantified due to the limitation of current GW methodology in calculating the total energy difference in between different magnetic phases. In ferromagnetic 3d elements, GW self-energy slightly reduces the d bandwidth and enhances the interactions while the same long-range feature is maintained. In antiferromagnetic transition-metal monoxides, QSGW significantly reduces the interaction strengths by enlarging the gap. Orbital-dependent magnetic force calculations show that the coupling between e g and the nominally-empty 4s orbital is noticeably large in MnO which is reminiscent of the discussion for cuprates regarding the role of Cu-4s state. This combination of magnetic force theory with quasiparticle self-consistent GW can be a useful tool to study various magnetic materials.
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Affiliation(s)
- Hongkee Yoon
- Department of Physics, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
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30
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Pourovskii LV. Electronic correlations in dense iron: from moderate pressure to Earth's core conditions. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:373001. [PMID: 31167170 DOI: 10.1088/1361-648x/ab274f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We discuss the role of dynamical many-electron effects in the physics of iron and iron-rich solid alloys under applied pressure on the basis of recent ab initio studies employing the dynamical mean-field theory (DMFT). We review in detail two particularly interesting regimes: first, a moderate pressure range up to 60 GPa and, second, the ultra-high pressure of about 360 GPa expected inside the solid inner core of Earth. Electronic correlations in iron under the moderate pressure of several tens GPa are discussed in the first section. DMFT-based methods predict an enhancement of electronic correlations at the pressure-induced body-centered cubic α to hexagonal close-packed [Formula: see text] phase transition. In particular, the electronic effective mass, scattering rate and electron-electron contribution to the electrical resistivity undergo a step-wise increase at the transition point. One also finds a significant many-body correction to the [Formula: see text]-Fe equation of state, thus clarifying the origin of discrepancies between previous DFT studies and experiment. An electronic topological transition is predicted to be induced in [Formula: see text]-Fe by many-electron effects; its experimental signatures are analyzed. The next section focuses on the geophysically relevant pressure-temperature regime of the Earth's inner core (EIC) corresponding to the extreme pressure of 360 GPa combined with temperatures up to 6000 K. The three iron allotropes ([Formula: see text], [Formula: see text] and face-centered-cubic [Formula: see text]) previously proposed as possible stable phases at such conditions are found to exhibit qualitatively different many-electron effects as evidenced by a strongly non-Fermi-liquid metallic state of [Formula: see text]-Fe and an almost perfect Fermi liquid in the case of [Formula: see text]-Fe. A recent active discussion on the electronic state and transport properties of [Formula: see text]-Fe at the EIC conditions is reviewed in details. Estimations for the dynamical many-electron contribution to the relative phase stability are presented. We also discuss the impact of a Ni admixture, which is expected to be present in the core matter. We conclude by outlining some limitation of the present DMFT-based framework relevant for studies of iron-base systems as well as perspective directions for further development.
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Affiliation(s)
- Leonid V Pourovskii
- CPHT, CNRS, Ecole Polytechnique, IP Paris, F-91128 Palaiseau, France. Collège de France, 11 place Marcelin Berthelot, 75005 Paris, France
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31
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Di Sabatino S, Berger JA, Romaniello P. Many-Body Effective Energy Theory: Photoemission at Strong Correlation. J Chem Theory Comput 2019; 15:5080-5086. [DOI: 10.1021/acs.jctc.9b00427] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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32
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Gaggioli CA, Stoneburner SJ, Cramer CJ, Gagliardi L. Beyond Density Functional Theory: The Multiconfigurational Approach To Model Heterogeneous Catalysis. ACS Catal 2019. [DOI: 10.1021/acscatal.9b01775] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Carlo Alberto Gaggioli
- Department of Chemistry, Chemical Theory Center and Supercomputing Institute, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455-0431, United States
| | - Samuel J. Stoneburner
- Department of Chemistry, Chemical Theory Center and Supercomputing Institute, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455-0431, United States
| | - Christopher J. Cramer
- Department of Chemistry, Chemical Theory Center and Supercomputing Institute, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455-0431, United States
| | - Laura Gagliardi
- Department of Chemistry, Chemical Theory Center and Supercomputing Institute, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455-0431, United States
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33
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Golze D, Dvorak M, Rinke P. The GW Compendium: A Practical Guide to Theoretical Photoemission Spectroscopy. Front Chem 2019; 7:377. [PMID: 31355177 PMCID: PMC6633269 DOI: 10.3389/fchem.2019.00377] [Citation(s) in RCA: 153] [Impact Index Per Article: 30.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Accepted: 05/08/2019] [Indexed: 12/22/2022] Open
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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Adler R, Kang CJ, Yee CH, Kotliar G. Correlated materials design: prospects and challenges. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2019; 82:012504. [PMID: 30138114 DOI: 10.1088/1361-6633/aadca4] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The design of correlated materials challenges researchers to combine the maturing, high throughput framework of DFT-based materials design with the rapidly-developing first-principles theory for correlated electron systems. We review the field of correlated materials, distinguishing two broad classes of correlation effects, static and dynamics, and describe methodologies to take them into account. We introduce a material design workflow, and illustrate it via examples in several materials classes, including superconductors, charge ordering materials and systems near an electronically driven metal to insulator transition, highlighting the interplay between theory and experiment with a view towards finding new materials. We review the statistical formulation of the errors of currently available methods to estimate formation energies. We formulate an approach for estimating a lower-bound for the probability of a new compound to form. Correlation effects have to be considered in all the material design steps. These include bridging between structure and property, obtaining the correct structure and predicting material stability. We introduce a post-processing strategy to take them into account.
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Affiliation(s)
- Ran Adler
- Department of Physics & Astronomy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, United States of America
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35
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Rusakov AA, Iskakov S, Tran LN, Zgid D. Self-Energy Embedding Theory (SEET) for Periodic Systems. J Chem Theory Comput 2018; 15:229-240. [DOI: 10.1021/acs.jctc.8b00927] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Alexander A. Rusakov
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Sergei Iskakov
- Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Lan Nguyen Tran
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, United States
- Ho Chi Minh City Institute of Physics, Vietnam Academy of Science and Technology (VAST), Ho Chi Minh City 70000, Vietnam
| | - Dominika Zgid
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, United States
- Center for Computational Quantum Physics, The Flatiron Institute, New York, New York 10010, United States
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36
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Senjean B, Nakatani N, Tsuchiizu M, Fromager E. Multiple impurities and combined local density approximations in site-occupation embedding theory. Theor Chem Acc 2018. [DOI: 10.1007/s00214-018-2368-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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37
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Abstract
Correlated electron materials display a rich variety of notable properties ranging from unconventional superconductivity to metal-insulator transitions. These properties are of interest from the point of view of applications but are hard to treat theoretically, as they result from multiple competing energy scales. Although possible in more weakly correlated materials, theoretical design and spectroscopy of strongly correlated electron materials have been a difficult challenge for many years. By treating all the relevant energy scales with sufficient accuracy, complementary advances in Green's functions and quantum Monte Carlo methods open a path to first-principles computational property predictions in this class of materials.
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Affiliation(s)
- Paul R C Kent
- Computational Sciences and Engineering Division and Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Gabriel Kotliar
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, NY 11973, USA. .,Department of Physics and Astronomy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
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38
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Stepanov EA, Brener S, Krien F, Harland M, Lichtenstein AI, Katsnelson MI. Effective Heisenberg Model and Exchange Interaction for Strongly Correlated Systems. PHYSICAL REVIEW LETTERS 2018; 121:037204. [PMID: 30085776 DOI: 10.1103/physrevlett.121.037204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Indexed: 06/08/2023]
Abstract
We consider the extended Hubbard model and introduce a corresponding Heisenberg-like problem written in terms of spin operators. The derived formalism is reminiscent of Anderson's idea of the effective exchange interaction and takes into account nonlocal correlation effects. The results for the exchange interaction and spin susceptibility in the magnetic phase are expressed in terms of single-particle quantities. This fact not only can be used for realistic calculations of multiband systems but also allows us to reconsider a general description of many-body effects in the most interesting physical regimes, where the physical properties of the system are dominated by collective (bosonic) fluctuations. In the strongly spin-polarized limit, when the local magnetic moment is well defined, the exchange interaction reduces to a standard expression of the density functional theory that has been successfully used in practical calculations of magnetic properties of real materials.
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Affiliation(s)
- E A Stepanov
- Radboud University, Institute for Molecules and Materials, 6525AJ Nijmegen, Netherlands
- Theoretical Physics and Applied Mathematics Department, Ural Federal University, Mira Street 19, 620002 Ekaterinburg, Russia
| | - S Brener
- Institute of Theoretical Physics, University of Hamburg, 20355 Hamburg, Germany
| | - F Krien
- Institute of Theoretical Physics, University of Hamburg, 20355 Hamburg, Germany
| | - M Harland
- Institute of Theoretical Physics, University of Hamburg, 20355 Hamburg, Germany
| | - A I Lichtenstein
- Theoretical Physics and Applied Mathematics Department, Ural Federal University, Mira Street 19, 620002 Ekaterinburg, Russia
- Institute of Theoretical Physics, University of Hamburg, 20355 Hamburg, Germany
| | - M I Katsnelson
- Radboud University, Institute for Molecules and Materials, 6525AJ Nijmegen, Netherlands
- Theoretical Physics and Applied Mathematics Department, Ural Federal University, Mira Street 19, 620002 Ekaterinburg, Russia
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39
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Tomczak JM. Thermoelectricity in correlated narrow-gap semiconductors. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:183001. [PMID: 29633717 DOI: 10.1088/1361-648x/aab284] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We review many-body effects, their microscopic origin, as well as their impact on thermoelectricity in correlated narrow-gap semiconductors. Members of this class-such as FeSi and FeSb2-display an unusual temperature dependence in various observables: insulating with large thermopowers at low temperatures, they turn bad metals at temperatures much smaller than the size of their gaps. This insulator-to-metal crossover is accompanied by spectral weight-transfers over large energies in the optical conductivity and by a gradual transition from activated to Curie-Weiss-like behaviour in the magnetic susceptibility. We show a retrospective of the understanding of these phenomena, discuss the relation to heavy-fermion Kondo insulators-such as Ce3Bi4Pt3 for which we present new results-and propose a general classification of paramagnetic insulators. From the latter, FeSi emerges as an orbital-selective Kondo insulator. Focussing on intermetallics such as silicides, antimonides, skutterudites, and Heusler compounds we showcase successes and challenges for the realistic simulation of transport properties in the presence of electronic correlations. Further, we explore new avenues in which electronic correlations may contribute to the improvement of thermoelectric performance.
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Affiliation(s)
- Jan M Tomczak
- Institute of Solid State Physics, TU Wien, A-1040 Vienna, Austria
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40
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Recent Progress in First-Principles Methods for Computing the Electronic Structure of Correlated Materials. COMPUTATION 2018. [DOI: 10.3390/computation6010026] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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41
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Variational structure of Luttinger-Ward formalism and bold diagrammatic expansion for Euclidean lattice field theory. Proc Natl Acad Sci U S A 2018; 115:2282-2286. [PMID: 29463752 DOI: 10.1073/pnas.1720782115] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The Luttinger-Ward functional was proposed more than five decades ago and has been used to formally justify most practically used Green's function methods for quantum many-body systems. Nonetheless, the very existence of the Luttinger-Ward functional has been challenged by recent theoretical and numerical evidence. We provide a rigorously justified Luttinger-Ward formalism, in the context of Euclidean lattice field theory. Using the Luttinger-Ward functional, the free energy can be variationally minimized with respect to Green's functions in its domain. We then derive the widely used bold diagrammatic expansion rigorously, without relying on formal arguments such as partial resummation of bare diagrams to infinite order.
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42
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Ayral T, Vučičević J, Parcollet O. Fierz Convergence Criterion: A Controlled Approach to Strongly Interacting Systems with Small Embedded Clusters. PHYSICAL REVIEW LETTERS 2017; 119:166401. [PMID: 29099214 DOI: 10.1103/physrevlett.119.166401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Indexed: 06/07/2023]
Abstract
We present an embedded-cluster method, based on the triply irreducible local expansion formalism. It turns the Fierz ambiguity, inherent to approaches based on a bosonic decoupling of local fermionic interactions, into a convergence criterion. It is based on the approximation of the three-leg vertex by a coarse-grained vertex computed from a self-consistently determined cluster impurity model. The computed self-energies are, by construction, continuous functions of momentum. We show that, in three interaction and doping regimes of the two-dimensional Hubbard model, self-energies obtained with clusters of size four only are very close to numerically exact benchmark results. We show that the Fierz parameter, which parametrizes the freedom in the Hubbard-Stratonovich decoupling, can be used as a quality control parameter. By contrast, the GW+extended dynamical mean field theory approximation with four cluster sites is shown to yield good results only in the weak-coupling regime and for a particular decoupling. Finally, we show that the vertex has spatially nonlocal components only at low Matsubara frequencies.
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Affiliation(s)
- Thomas Ayral
- Physics and Astronomy Department, Rutgers University, Piscataway, New Jersey 08854, USA
- Institut de Physique Théorique (IPhT), CEA, CNRS, UMR 3681, 91191 Gif-sur-Yvette, France
| | - Jaksa Vučičević
- Institut de Physique Théorique (IPhT), CEA, CNRS, UMR 3681, 91191 Gif-sur-Yvette, France
- Scientific Computing Laboratory, Center for the Study of Complex Systems, Institute of Physics Belgrade, University of Belgrade, Pregrevica 118, 11080 Belgrade, Serbia
| | - Olivier Parcollet
- Institut de Physique Théorique (IPhT), CEA, CNRS, UMR 3681, 91191 Gif-sur-Yvette, France
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43
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Gunnarsson O, Rohringer G, Schäfer T, Sangiovanni G, Toschi A. Breakdown of Traditional Many-Body Theories for Correlated Electrons. PHYSICAL REVIEW LETTERS 2017; 119:056402. [PMID: 28949722 DOI: 10.1103/physrevlett.119.056402] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Indexed: 06/07/2023]
Abstract
Starting from the (Hubbard) model of an atom, we demonstrate that the uniqueness of the mapping from the interacting to the noninteracting Green function, G→G_{0}, is strongly violated, by providing numerous explicit examples of different G_{0} leading to the same physical G. We argue that there are indeed infinitely many such G_{0}, with numerous crossings with the physical solution. We show that this rich functional structure is directly related to the divergence of certain classes of (irreducible vertex) diagrams, with important consequences for traditional many-body physics based on diagrammatic expansions. Physically, we ascribe the onset of these highly nonperturbative manifestations to the progressive suppression of the charge susceptibility induced by the formation of local magnetic moments and/or resonating valence bond (RVB) states in strongly correlated electron systems.
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Affiliation(s)
- O Gunnarsson
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, D-70569 Stuttgart, Germany
| | - G Rohringer
- Russian Quantum Center, Novaya street, 100, Skolkovo, Moscow region 143025, Russia
| | - T Schäfer
- Institute of solid state physics, Technische Universität Wien, 1040 Vienna, Austria
| | - G Sangiovanni
- Institute of Physics and Astrophysics, University of Würzburg, Würzburg 97074, Germany
| | - A Toschi
- Institute of solid state physics, Technische Universität Wien, 1040 Vienna, Austria
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44
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Hausoel A, Karolak M, Şaşιoğlu E, Lichtenstein A, Held K, Katanin A, Toschi A, Sangiovanni G. Local magnetic moments in iron and nickel at ambient and Earth's core conditions. Nat Commun 2017; 8:16062. [PMID: 28799538 PMCID: PMC5510222 DOI: 10.1038/ncomms16062] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Accepted: 05/25/2017] [Indexed: 12/01/2022] Open
Abstract
Some Bravais lattices have a particular geometry that can slow down the motion of Bloch electrons by pre-localization due to the band-structure properties. Another known source of electronic localization in solids is the Coulomb repulsion in partially filled d or f orbitals, which leads to the formation of local magnetic moments. The combination of these two effects is usually considered of little relevance to strongly correlated materials. Here we show that it represents, instead, the underlying physical mechanism in two of the most important ferromagnets: nickel and iron. In nickel, the van Hove singularity has an unexpected impact on the magnetism. As a result, the electron-electron scattering rate is linear in temperature, in violation of the conventional Landau theory of metals. This is true even at Earth's core pressures, at which iron is instead a good Fermi liquid. The importance of nickel in models of geomagnetism may have therefore to be reconsidered.
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Affiliation(s)
- A. Hausoel
- Institut für Theoretische Physik und Astrophysik, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - M. Karolak
- Institut für Theoretische Physik und Astrophysik, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - E. Şaşιoğlu
- Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, 52425 Jülich, Germany
- Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, 06120 Halle (Saale), Germany
| | - A. Lichtenstein
- Institut für Theoretische Physik, Universität Hamburg, Jungiusstrasse 9, 20355 Hamburg, Germany
| | - K. Held
- Institute of Solid State Physics, TU Wien, 1040 Vienna, Austria
| | - A. Katanin
- M. N. Mikheev Institute of Metal Physics, 620990 Ekaterinburg, Russia
- Ural Federal University, 620002 Ekaterinburg, Russia
| | - A. Toschi
- Institute of Solid State Physics, TU Wien, 1040 Vienna, Austria
| | - G. Sangiovanni
- Institut für Theoretische Physik und Astrophysik, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
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45
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Martins C, Aichhorn M, Biermann S. Coulomb correlations in 4d and 5d oxides from first principles-or how spin-orbit materials choose their effective orbital degeneracies. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:263001. [PMID: 28262638 DOI: 10.1088/1361-648x/aa648f] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The interplay of spin-orbit coupling and Coulomb correlations has become a hot topic in condensed matter theory and is especially important in 4d and 5d transition metal oxides, like iridates or rhodates. Here, we review recent advances in dynamical mean-field theory (DMFT)-based electronic structure calculations for treating such compounds, introducing all necessary implementation details. We also discuss the evaluation of Hubbard interactions in spin-orbit materials. As an example, we perform DMFT calculations on insulating strontium iridate (Sr2IrO4) and its 4d metallic counterpart, strontium rhodate (Sr2RhO4). While a Mott-insulating state is obtained for Sr2IrO4 in its paramagnetic phase, the spectral properties and Fermi surfaces obtained for Sr2RhO4 show excellent agreement with available experimental data. Finally, we discuss the electronic structure of these two compounds by introducing the notion of effective spin-orbital degeneracy as the key quantity that determines the correlation strength. We stress that effective spin-orbital degeneracy introduces an additional axis into the conventional picture of a phase diagram based on filling and on the ratio of interactions to bandwidth, analogous to the degeneracy-controlled Mott transition in d1 perovskites.
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Affiliation(s)
- C Martins
- Laboratoire de Chimie et Physique Quantiques, UMR 5626, Université Paul Sabatier, 118 route de Narbonne, 31400 Toulouse, France
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46
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Golež D, Boehnke L, Strand HUR, Eckstein M, Werner P. Nonequilibrium GW+EDMFT: Antiscreening and Inverted Populations from Nonlocal Correlations. PHYSICAL REVIEW LETTERS 2017; 118:246402. [PMID: 28665669 DOI: 10.1103/physrevlett.118.246402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Indexed: 06/07/2023]
Abstract
We study the dynamics of screening in photodoped Mott insulators with long-ranged interactions using a nonequilibrium implementation of the GW plus extended dynamical mean-field theory formalism. Our study demonstrates that the complex interplay of the injected carriers with bosonic degrees of freedom (charge fluctuations) can result in long-lived transient states with properties that are distinctly different from those of thermal equilibrium states. Systems with strong nonlocal interactions are found to exhibit a self-sustained population inversion of the doublons and holes. This population inversion leads to low-energy antiscreening which can be detected in time-resolved electron-energy-loss spectra.
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Affiliation(s)
- Denis Golež
- Department of Physics, University of Fribourg, 1700 Fribourg, Switzerland
| | - Lewin Boehnke
- Department of Physics, University of Fribourg, 1700 Fribourg, Switzerland
| | - Hugo U R Strand
- Department of Physics, University of Fribourg, 1700 Fribourg, Switzerland
| | - Martin Eckstein
- Max-Planck Institute for the Structure and Dynamics of Matter, 22761 Hamburg, Germany
| | - Philipp Werner
- Department of Physics, University of Fribourg, 1700 Fribourg, Switzerland
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47
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Moser S, Nomura Y, Moreschini L, Gatti G, Berger H, Bugnon P, Magrez A, Jozwiak C, Bostwick A, Rotenberg E, Biermann S, Grioni M. Electronic Phase Separation and Dramatic Inverse Band Renormalization in the Mixed-Valence Cuprate LiCu_{2}O_{2}. PHYSICAL REVIEW LETTERS 2017; 118:176404. [PMID: 28498707 DOI: 10.1103/physrevlett.118.176404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Indexed: 06/07/2023]
Abstract
We measured, by angle-resolved photoemission spectroscopy, the electronic structure of LiCu_{2}O_{2}, a mixed-valence cuprate where planes of Cu(I) (3d^{10}) ions are sandwiched between layers containing one-dimensional edge-sharing Cu(II) (3d^{9}) chains. We find that the Cu(I)- and Cu(II)-derived electronic states form separate electronic subsystems, in spite of being coupled by bridging O ions. The valence band, of the Cu(I) character, disperses within the charge-transfer gap of the strongly correlated Cu(II) states, displaying an unprecedented 250% broadening of the bandwidth with respect to the predictions of density functional theory. Our observation is at odds with the widely accepted tenet of many-body theory that correlation effects generally yield narrower bands and larger electron masses and suggests that present-day electronic structure techniques provide an intrinsically inappropriate description of ligand-to-d hybridizations in late transition metal oxides.
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Affiliation(s)
- S Moser
- Institute of Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
- Advanced Light Source (ALS), Berkeley, California 94720, USA
| | - Y Nomura
- Centre de Physique Théorique, Ecole Polytechnique, CNRS-UMR7644, Université Paris-Saclay, 91128 Palaiseau, France
- Collège de France, 11 place Marcelin Berthelot, 75005 Paris, France
| | - L Moreschini
- Advanced Light Source (ALS), Berkeley, California 94720, USA
| | - G Gatti
- Institute of Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - H Berger
- Institute of Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - P Bugnon
- Institute of Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - A Magrez
- Institute of Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - C Jozwiak
- Advanced Light Source (ALS), Berkeley, California 94720, USA
| | - A Bostwick
- Advanced Light Source (ALS), Berkeley, California 94720, USA
| | - E Rotenberg
- Advanced Light Source (ALS), Berkeley, California 94720, USA
| | - S Biermann
- Centre de Physique Théorique, Ecole Polytechnique, CNRS-UMR7644, Université Paris-Saclay, 91128 Palaiseau, France
- Collège de France, 11 place Marcelin Berthelot, 75005 Paris, France
| | - M Grioni
- Institute of Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
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48
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Wang D, Zheng Y, Tian J, Jing T, Kan W, Hu Y. Theoretical calculation and experiment study on the electronic structure, microstructures and photocatalytic activity of N–Al codoped TiO 2. RSC Adv 2017. [DOI: 10.1039/c7ra07815c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
To more accurately demonstrate how the electronic structure was changed and to explain the origin of the enhanced photocatalytic activity by N–Al codoped TiO2, we investigated N, Al monodoped, and codoped TiO2by theoretical calculation and experiments.
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Affiliation(s)
- Dandan Wang
- College of Chemistry and Chemical Engineering
- Qiqihar University
- Qiqihar
- China
| | - Yongjie Zheng
- College of Chemistry and Chemical Engineering
- Qiqihar University
- Qiqihar
- China
| | - Jingzhi Tian
- College of Chemistry and Chemical Engineering
- Qiqihar University
- Qiqihar
- China
| | - Tao Jing
- College of Chemistry and Chemical Engineering
- Qiqihar University
- Qiqihar
- China
| | - Wei Kan
- College of Chemistry and Chemical Engineering
- Qiqihar University
- Qiqihar
- China
| | - Yi Hu
- College of Chemistry and Chemical Engineering
- Qiqihar University
- Qiqihar
- China
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49
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Werner P, Casula M. Dynamical screening in correlated electron systems-from lattice models to realistic materials. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2016; 28:383001. [PMID: 27440180 DOI: 10.1088/0953-8984/28/38/383001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Recent progress in treating the dynamical nature of the screened Coulomb interaction in strongly correlated lattice models and materials is reviewed with a focus on computational schemes based on the dynamical mean field approximation. We discuss approximate and exact methods for the solution of impurity models with retarded interactions, and explain how these models appear as auxiliary problems in various extensions of the dynamical mean field formalism. The current state of the field is illustrated with results from recent applications of these schemes to U-V Hubbard models and correlated materials.
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Affiliation(s)
- Philipp Werner
- Department of Physics, University of Fribourg, Chemin du Musée 3, 1700 Fribourg, Switzerland
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50
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Nguyen Lan T, Kananenka AA, Zgid D. Rigorous Ab Initio Quantum Embedding for Quantum Chemistry Using Green’s Function Theory: Screened Interaction, Nonlocal Self-Energy Relaxation, Orbital Basis, and Chemical Accuracy. J Chem Theory Comput 2016; 12:4856-4870. [DOI: 10.1021/acs.jctc.6b00638] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Tran Nguyen Lan
- Department of Chemistry and ‡Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Alexei A. Kananenka
- Department of Chemistry and ‡Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Dominika Zgid
- Department of Chemistry and ‡Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, United States
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