1
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Hariki A, Dal Din A, Amin OJ, Yamaguchi T, Badura A, Kriegner D, Edmonds KW, Campion RP, Wadley P, Backes D, Veiga LSI, Dhesi SS, Springholz G, Šmejkal L, Výborný K, Jungwirth T, Kuneš J. X-Ray Magnetic Circular Dichroism in Altermagnetic α-MnTe. PHYSICAL REVIEW LETTERS 2024; 132:176701. [PMID: 38728732 DOI: 10.1103/physrevlett.132.176701] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 02/01/2024] [Accepted: 03/20/2024] [Indexed: 05/12/2024]
Abstract
Altermagnetism is a recently identified magnetic symmetry class combining characteristics of conventional collinear ferromagnets and antiferromagnets, that were regarded as mutually exclusive, and enabling phenomena and functionalities unparalleled in either of the two traditional elementary magnetic classes. In this work we use symmetry, ab initio theory, and experiments to explore x-ray magnetic circular dichroism (XMCD) in the altermagnetic class. As a representative material for our XMCD study we choose α-MnTe with compensated antiparallel magnetic order in which an anomalous Hall effect has been already demonstrated. We predict and experimentally confirm a characteristic XMCD line shape for compensated moments lying in a plane perpendicular to the light propagation vector. Our results highlight the distinct phenomenology in altermagnets of this time-reversal symmetry breaking response, and its potential utility for element-specific spectroscopy and microscopy.
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Affiliation(s)
- A Hariki
- Department of Physics and Electronics, Graduate School of Engineering, Osaka Metropolitan University, 1-1 Gakuen-cho, Nakaku, Sakai, Osaka 599-8531, Japan
| | - A Dal Din
- School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - O J Amin
- School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - T Yamaguchi
- Department of Physics and Electronics, Graduate School of Engineering, Osaka Metropolitan University, 1-1 Gakuen-cho, Nakaku, Sakai, Osaka 599-8531, Japan
| | - A Badura
- Institute of Physics, Czech Academy of Sciences, Cukrovarnická 10, 162 00 Praha 6 Czech Republic
| | - D Kriegner
- Institute of Physics, Czech Academy of Sciences, Cukrovarnická 10, 162 00 Praha 6 Czech Republic
| | - K W Edmonds
- School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - R P Campion
- School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - P Wadley
- School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - D Backes
- Diamond Light Source, Chilton OX11 0DE, United Kingdom
| | - L S I Veiga
- Diamond Light Source, Chilton OX11 0DE, United Kingdom
| | - S S Dhesi
- Diamond Light Source, Chilton OX11 0DE, United Kingdom
| | - G Springholz
- Institute of Semiconductor and Solid State Physics, Johannes Kepler University Linz, Altenbergerstraße 69, 4040 Linz, Austria
| | - L Šmejkal
- Institute of Physics, Czech Academy of Sciences, Cukrovarnická 10, 162 00 Praha 6 Czech Republic
- Institut für Physik, Johannes Gutenberg Universität Mainz, D-55099 Mainz, Germany
| | - K Výborný
- Institute of Physics, Czech Academy of Sciences, Cukrovarnická 10, 162 00 Praha 6 Czech Republic
| | - T Jungwirth
- School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, United Kingdom
- Institute of Physics, Czech Academy of Sciences, Cukrovarnická 10, 162 00 Praha 6 Czech Republic
| | - J Kuneš
- Institute for Solid State Physics, TU Wien, 1040 Vienna, Austria
- Department of Condensed Matter Physics, Faculty of Science, Masaryk University, Kotlářská 2, 611 37 Brno, Czechia
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2
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Liu BL, Wang YC, Liu Y, Liu HF, Song HF. Doubly Screened Coulomb Correction Approach for Strongly Correlated Systems. J Phys Chem Lett 2023; 14:8930-8939. [PMID: 37768131 DOI: 10.1021/acs.jpclett.3c02035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/29/2023]
Abstract
Strongly correlated systems containing d/f electrons present a challenge to conventional density functional theory such as the local density approximation or generalized gradient approximation. We developed a doubly screened Coulomb correction (DSCC) approach to perform on-site Coulomb interaction correction for strongly correlated materials. The on-site Coulomb interaction between localized d/f electrons is self-consistently determined from a model dielectric function that includes both the static dielectric and Thomas-Fermi screening. We applied DSCC to simulate the electronic and magnetic properties of typical 3d, 4f, and 5f strongly correlated systems. The accuracy of DSCC is comparable to that of hybrid functionals but an order of magnitude faster. In addition, DSCC can reflect the difference in the Coulomb interaction between metallic and insulating situations, similar to the popular but computationally expensive constrained random phase approximation approach. This feature suggests that DSCC is also a promising method for simulating Coulomb interaction parameters.
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Affiliation(s)
- Bei-Lei Liu
- Laboratory of Computational Physics, Institute of Applied Physics and Computational Mathematics, Beijing 100088, China
- School of Mathematical Sciences, Beijing Normal University, Beijing 100875, China
| | - Yue-Chao Wang
- Laboratory of Computational Physics, Institute of Applied Physics and Computational Mathematics, Beijing 100088, China
| | - Yu Liu
- Laboratory of Computational Physics, Institute of Applied Physics and Computational Mathematics, Beijing 100088, China
| | - Hai-Feng Liu
- Laboratory of Computational Physics, Institute of Applied Physics and Computational Mathematics, Beijing 100088, China
| | - Hai-Feng Song
- Laboratory of Computational Physics, Institute of Applied Physics and Computational Mathematics, Beijing 100088, China
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3
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Park TJ, Deng S, Manna S, Islam ANMN, Yu H, Yuan Y, Fong DD, Chubykin AA, Sengupta A, Sankaranarayanan SKRS, Ramanathan S. Complex Oxides for Brain-Inspired Computing: A Review. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2203352. [PMID: 35723973 DOI: 10.1002/adma.202203352] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Revised: 06/02/2022] [Indexed: 06/15/2023]
Abstract
The fields of brain-inspired computing, robotics, and, more broadly, artificial intelligence (AI) seek to implement knowledge gleaned from the natural world into human-designed electronics and machines. In this review, the opportunities presented by complex oxides, a class of electronic ceramic materials whose properties can be elegantly tuned by doping, electron interactions, and a variety of external stimuli near room temperature, are discussed. The review begins with a discussion of natural intelligence at the elementary level in the nervous system, followed by collective intelligence and learning at the animal colony level mediated by social interactions. An important aspect highlighted is the vast spatial and temporal scales involved in learning and memory. The focus then turns to collective phenomena, such as metal-to-insulator transitions (MITs), ferroelectricity, and related examples, to highlight recent demonstrations of artificial neurons, synapses, and circuits and their learning. First-principles theoretical treatments of the electronic structure, and in situ synchrotron spectroscopy of operating devices are then discussed. The implementation of the experimental characteristics into neural networks and algorithm design is then revewed. Finally, outstanding materials challenges that require a microscopic understanding of the physical mechanisms, which will be essential for advancing the frontiers of neuromorphic computing, are highlighted.
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Affiliation(s)
- Tae Joon Park
- School of Materials Engineering, Purdue University, West Lafayette, IN, 47907, USA
| | - Sunbin Deng
- School of Materials Engineering, Purdue University, West Lafayette, IN, 47907, USA
| | - Sukriti Manna
- Center for Nanoscale Materials, Argonne National Laboratory, Argonne, IL, 60439, USA
| | - A N M Nafiul Islam
- Department of Electrical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Haoming Yu
- School of Materials Engineering, Purdue University, West Lafayette, IN, 47907, USA
| | - Yifan Yuan
- School of Materials Engineering, Purdue University, West Lafayette, IN, 47907, USA
| | - Dillon D Fong
- Materials Science Division, Argonne National Laboratory, Lemont, IL, 60439, USA
| | - Alexander A Chubykin
- Department of Biological Sciences, Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN, 47907, USA
| | - Abhronil Sengupta
- Department of Electrical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Subramanian K R S Sankaranarayanan
- Center for Nanoscale Materials, Argonne National Laboratory, Argonne, IL, 60439, USA
- Department of Mechanical and Industrial Engineering, University of Illinois Chicago, Chicago, IL, 60607, USA
| | - Shriram Ramanathan
- School of Materials Engineering, Purdue University, West Lafayette, IN, 47907, USA
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4
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Wu W, Wang X, Zeng Z. The magnetic properties of pressurized CsV 3Sb 5 calculated by using a hybrid functional. Phys Chem Chem Phys 2022; 24:18179-18184. [PMID: 35861250 DOI: 10.1039/d2cp01763f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Based on the hybrid functional, we find that at 0 GPa, pristine CsV3Sb5 has a magnetic moment of 0.28 μB per vanadium atom, which is suppressed at a pressure of 2.5 GPa resulting in a spin-crossover. Since the ground state of CsV3Sb5 with charge density wave (CDW) distortion is a non-magnetic state, the magnetic moment of V atoms in pristine CsV3Sb5 will be suppressed by the temperature-induced CDW transition at 94 K. The schematic evolution of magnetic moments as functions of pressure and temperature is presented. At low temperature, CsV3Sb5 is a rare example of materials hosting a pressure-induced magnetic moment, and we suggest that the effects of magnetic moments of V atoms should be considered for understanding its properties.
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Affiliation(s)
- Wenfeng Wu
- Key Laboratory of Materials Physics, Institute of Solid State Physics, HFIPS, Chinese Academy of Sciences, Hefei 230031, China. .,Science Island Branch of Graduate School, University of Science and Technology of China, Hefei 230026, China
| | - Xianlong Wang
- Key Laboratory of Materials Physics, Institute of Solid State Physics, HFIPS, Chinese Academy of Sciences, Hefei 230031, China. .,Science Island Branch of Graduate School, University of Science and Technology of China, Hefei 230026, China
| | - Zhi Zeng
- Key Laboratory of Materials Physics, Institute of Solid State Physics, HFIPS, Chinese Academy of Sciences, Hefei 230031, China. .,Science Island Branch of Graduate School, University of Science and Technology of China, Hefei 230026, China
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5
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Higashi K, Yamaguchi T, Takahashi Y, Hariki A. Charge-transfer effect in Fe 2 pcore-level x-ray photoemission spectra of trivalent Fe oxides: LDA + DMFT study. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 34:375602. [PMID: 35793685 DOI: 10.1088/1361-648x/ac7f18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 07/06/2022] [Indexed: 06/15/2023]
Abstract
Motivated by recent hard x-ray photoemission spectroscopy (XPS) experiment for trivalent Fe oxides Sr2FeMoO6(ferrimagnetic correlated metal) and LaFeO3(antiferromagnetic Mott insulator) (Phuyalet al2021J. Phys. Chem.C12511249-56), we present a theoretical analysis of the Fe 2pcore-level spectra using a computational method based on local density approximation combined with dynamical mean-field theory. We find that a nonlocal screening (NLS) effect in the XPS final states is crucial for interpreting the experimental XPS result of both the Fe oxides. A close relationship between the NLS feature in core-level spectra and a long-range magnetic ordering is emphasized.
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Affiliation(s)
- Keisuke Higashi
- Department of Physics and Electronics, Graduate School of Engineering, Osaka Metropolitan University, 1-1 Gakuen-cho, Nakaku, Sakai, Osaka 599-8531, Japan
| | - Tatsuya Yamaguchi
- Department of Physics and Electronics, Graduate School of Engineering, Osaka Metropolitan University, 1-1 Gakuen-cho, Nakaku, Sakai, Osaka 599-8531, Japan
| | - Yoshihiro Takahashi
- Department of Physics and Electronics, Graduate School of Engineering, Osaka Metropolitan University, 1-1 Gakuen-cho, Nakaku, Sakai, Osaka 599-8531, Japan
| | - Atsushi Hariki
- Department of Physics and Electronics, Graduate School of Engineering, Osaka Metropolitan University, 1-1 Gakuen-cho, Nakaku, Sakai, Osaka 599-8531, Japan
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6
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Pressure-induced high-spin/low-spin disproportionated state in the Mott insulator FeBO 3. Sci Rep 2022; 12:9647. [PMID: 35689001 PMCID: PMC9187741 DOI: 10.1038/s41598-022-13507-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Accepted: 05/25/2022] [Indexed: 11/12/2022] Open
Abstract
The pressure-induced Mott insulator-to-metal transitions are often accompanied by a collapse of magnetic interactions associated with delocalization of 3d electrons and high-spin to low-spin (HS-LS) state transition. Here, we address a long-standing controversy regarding the high-pressure behavior of an archetypal Mott insulator FeBO3 and show the insufficiency of a standard theoretical approach assuming a conventional HS-LS transition for the description of the electronic properties of the Mott insulators at high pressures. Using high-resolution x-ray diffraction measurements supplemented by Mössbauer spectroscopy up to pressures ~ 150 GPa, we document an unusual electronic state characterized by a “mixed” HS/LS state with a stable abundance ratio realized in the \documentclass[12pt]{minimal}
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\begin{document}$$R\overline{3 }c$$\end{document}R3¯c crystal structure with a single Fe site within a wide pressure range of ~ 50–106 GPa. Our results imply an unconventional cooperative (and probably dynamical) nature of the ordering of the HS/LS Fe sites randomly distributed over the lattice, resulting in frustration of magnetic moments.
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7
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Xia C, Chen Y, Chen H. Pressure-induced metal-insulator transition in oxygen-deficient LiNbO 3-type ferroelectrics. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 34:025501. [PMID: 34624871 DOI: 10.1088/1361-648x/ac2e30] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Accepted: 10/08/2021] [Indexed: 06/13/2023]
Abstract
Hydrostatic pressure and oxygen vacancies usually have deleterious effects on ferroelectric materials because both tend to reduce their polarization. In this work we use first-principles calculations to study an important class of ferroelectric materials-LiNbO3-type ferroelectrics (LiNbO3as the prototype), and find that in oxygen-deficient LiNbO3-δ, hydrostatic pressure induces an unexpected metal-insulator transition between 8 and 9 GPa. Our calculations also find that strong polar displacements persist in both metallic and insulating oxygen-deficient LiNbO3-δand the size of polar displacements is comparable to pristine LiNbO3under the same pressure. These properties are distinct from widely used perovskite ferroelectric oxide BaTiO3, whose polarization is quickly suppressed by hydrostatic pressure and/or oxygen vacancies. The anomalous pressure-driven metal-insulator transition in oxygen-deficient LiNbO3-δarises from the change of an oxygen vacancy defect state. Hydrostatic pressure increases the polar displacements of oxygen-deficient LiNbO3-δ, which reduces the band width of the defect state and eventually turns it into an in-gap state. In the insulating phase, the in-gap state is further pushed away from the conduction band edge under hydrostatic pressure, which increases the fundamental gap. Our work shows that for LiNbO3-type strong ferroelectrics, oxygen vacancies and hydrostatic pressure combined can lead to new phenomena and potential functions, in contrast to the harmful effects occurring to perovskite ferroelectric oxides such as BaTiO3.
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Affiliation(s)
- Chengliang Xia
- Department of Mechanical Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, People's Republic of China
- NYU-ECNU Institute of Physics, NYU Shanghai, Shanghai, 200062, People's Republic of China
| | - Yue Chen
- Department of Mechanical Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, People's Republic of China
| | - Hanghui Chen
- NYU-ECNU Institute of Physics, NYU Shanghai, Shanghai, 200062, People's Republic of China
- Department of Physics, New York University, New York 10003, United States of America
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8
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Chen L, Zhao L, Qiu X, Zhang Q, Liu K, Lin Q, Wang G. Quasi-One-Dimensional Structure and Possible Helical Antiferromagnetism of RbMn 6Bi 5. Inorg Chem 2021; 60:12941-12949. [PMID: 34436872 DOI: 10.1021/acs.inorgchem.1c01318] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Quasi-one-dimensional materials exhibit not only unique crystal structure but also abundant physical properties such as charge density wave, Luttinger liquid, and superconductivity. Here we report the discovery, structure, and physical properties of a new manganese-based quasi-one-dimensional material RbMn6Bi5, which crystallizes in a monoclinic space group C2/m (No. 12) with lattice parameters a = 23.286(5) Å, b = 4.6215(9) Å, c = 13.631(3) Å, and β = 125.00(3)°. The structure features [Mn6Bi5]-1 double-walled column extending along the [010] direction, together with Bi-Bi homoatomic bonds linking the columns and the countercation Rb+. The temperature-dependent resistivity clearly indicates a significant resistivity anisotropy for RbMn6Bi5, whereas the magnetic susceptibility and specific heat measurements show that RbMn6Bi5 is antiferromagnetic below 82 K. The density functional theory calculations indicate that RbMn6Bi5 is a quasi-one-dimensional metal with possible helical antiferromagnetic configuration. The discovery of RbMn6Bi5 confirms the viability of discovering new quasi-one-dimensional materials in manganese-based compounds.
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Affiliation(s)
- Long Chen
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Linlin Zhao
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiaole Qiu
- Department of Physics and Beijing Key Laboratory of Optoelectronic Functional Materials & Micro-nano Devices, Renmin University of China, Beijing 100872, China
| | - Qinghua Zhang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Kai Liu
- Department of Physics and Beijing Key Laboratory of Optoelectronic Functional Materials & Micro-nano Devices, Renmin University of China, Beijing 100872, China
| | - Qisheng Lin
- Ames Laboratory, U.S. Department of Energy, Ames, Iowa 50011, United States.,Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
| | - Gang Wang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.,School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.,Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
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9
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Li L, Zhao X, Bao K, Duan D, Cui T. Pressure-Induced Transition from Spin to Superconducting States in Novel MnN 2. ACS OMEGA 2021; 6:21830-21836. [PMID: 34471785 PMCID: PMC8388077 DOI: 10.1021/acsomega.1c03583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Accepted: 08/09/2021] [Indexed: 06/13/2023]
Abstract
The connection between magnetism and superconductivity has long been discussed since the discovery of Fe-based superconductors. Here, we report the discovery of a pressure-induced transition from a spin to a superconducting state in novel MnN2 based on ab initio calculations. The superconducting state can be obtained in two ways: the first is the pressure-induced transition from an AFM-P21/m to an NM-I4/mmm phase at 30 GPa, while the other is the pressure-induced transition from an FM-I4/mmm phase to magnetic vanishing at 14 GPa, which leads to a structural transition with the distortion of octahedrons to tetragonal pyramids. NM-I4/mmm-MnN2 is superconductive with T c ≈ 17.6 K at 0 GPa. In the second way, electronic structure calculations indicate that the system transforms from a high-spin state to a low-spin state due to increasing crystal-field splitting, causing disappearance of magnetism; more electron occupancy around the Fermi level drives the emergence of superconductivity. Remarkably, I4/mmm-MnN2 can achieve mutual spin-to-superconducting state transformation by pressure. Moreover, the AFM-P21/m-MnN2 phase is extremely incompressible with the hardness above 20 GPa. Our results provide a reasonable and systematic interpretation for the connection between magnetism and superconductivity and give clues for achieving spin-to-superconducting switching materials with certain crystal features.
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Affiliation(s)
- Li Li
- State
Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun 130012, China
| | - Xingbin Zhao
- State
Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun 130012, China
| | - Kuo Bao
- State
Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun 130012, China
| | - Defang Duan
- State
Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun 130012, China
| | - Tian Cui
- State
Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun 130012, China
- Institute
of High Pressure Physics, School of Physical Science and Technology, Ningbo University, Ningbo 315211, China
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10
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Jiang Z, Wang Y, Jiang D, Li C, Liu K, Wen T, Xiao Y, Chow P, Li S, Wang Y. Pressure-Driven Sequential Lattice Collapse and Magnetic Collapse in Transition-Metal-Intercalated Compounds Fe xNbS 2. J Phys Chem Lett 2021; 12:6348-6353. [PMID: 34228936 DOI: 10.1021/acs.jpclett.1c01220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Volume collapse under high pressure is an intriguing phenomenon involving subtle interplay between lattice, spin, and charge. The two most important causes of volume collapse are lattice collapse (low-density to high-density) and magnetic collapse (high-spin to low-spin). Herein we report the pressure-driven sequential volume collapses in partially intercalated FexNbS2 (x = 1/4, 1/3, 1/2, 2/3). Because of the distinct interlayer atomic occupancy, the low-iron-content samples exhibit both lattice and magnetic collapses under compression, whereas the high-iron-content samples exhibit only one magnetic collapse. Theoretical calculations indicate that the low-pressure volume collapses for x = 1/4 and x = 1/3 are lattice collapses, and the high-pressure volume collapses for all four samples are magnetic collapses. The magnetic collapse involving the high-spin to low-spin crossover of Fe2+ has also been verified by in situ X-ray emission measurements. Integrating two distinct volume collapses into one material provides a rare playground of lattice, spin, and charge.
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Affiliation(s)
- Zimin Jiang
- Center for High Pressure Science and Technology Advanced Research (HPSTAR), Beijing 100094, China
| | - Yiming Wang
- Center for High Pressure Science and Technology Advanced Research (HPSTAR), Beijing 100094, China
| | - Dequan Jiang
- Center for High Pressure Science and Technology Advanced Research (HPSTAR), Beijing 100094, China
| | - Chen Li
- Center for High Pressure Science and Technology Advanced Research (HPSTAR), Beijing 100094, China
| | - Ke Liu
- Center for High Pressure Science and Technology Advanced Research (HPSTAR), Beijing 100094, China
| | - Ting Wen
- Center for High Pressure Science and Technology Advanced Research (HPSTAR), Beijing 100094, China
| | - Yuming Xiao
- HPCAT, X-ray Science Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Paul Chow
- HPCAT, X-ray Science Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Shuai Li
- Academy for Advanced Interdisciplinary Studies, Shenzhen Key Laboratory of Solid state Batteries, Guangdong Provincial Key Laboratory of Energy Materials for Electric Power, Southern University of Science and Technology, Shenzhen 518055, China
| | - Yonggang Wang
- Center for High Pressure Science and Technology Advanced Research (HPSTAR), Beijing 100094, China
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11
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Zhang H, Niu C, Zhang J, Zou L, Zeng Z, Wang X. Spin-crossover induced ferromagnetism and layer stacking-order change in pressurized 2D antiferromagnet MnPS 3. Phys Chem Chem Phys 2021; 23:9679-9685. [PMID: 33624668 DOI: 10.1039/d0cp04917d] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Spin-crossover combined with metal-insulator transition and superconductivity has been found in 2D transition-metal phosphorous trichalcogenides when tuning them by high pressure. Simulation of such intriguing spin-crossover behaviors is crucial to understanding the mechanism. The Hubbard U correction is widely used to describe the strong on-site Coulomb interaction in the d electrons of transition-metal compounds, while the U values are sensitive to the crystal field and spin state varying greatly with pressure. In this work, we show that taking MnPS3 as an example and based on a uniform parameter set, the hybrid functional calculations give a spin-crossover pressure of 35 GPa consistent with experimental observation (30 GPa), which is less than half of the existing reported value (63 GPa) using the Hubbard U correction. Notably, we find a spin-crossover induced transition from an antiferromagnetic semiconductor with monoclinic stacking-order to a ferromagnetic semiconductor with rhombohedral stacking-order, and the ferromagnetism originates from the partially occupied t2g orbitals. Different from previous understanding, the Mott metal-insulator transition of MnPS3 does not occur simultaneously with the spin-crossover but in a pressurized low-spin phase.
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Affiliation(s)
- Hanxing Zhang
- Key Laboratory of Materials Physics, Institute of Solid State Physics, HFIPS, Chinese Academy of Sciences, Hefei 230031, China.
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12
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Yoon S, Jin K, Lee S, Nam KT, Kim M, Kwon YK. Effects of paramagnetic fluctuations on the thermochemistry of MnO(100) surfaces in the oxygen evolution reaction. Phys Chem Chem Phys 2021; 23:859-865. [PMID: 33074274 DOI: 10.1039/d0cp03779f] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We investigated the effects of paramagnetic (PM) fluctuations on the thermochemistry of the MnO(100) surface in the oxygen evolution reaction (OER) using the "noncollinear magnetic sampling method plus U" (NCMSM+U). Various physical properties, such as the electronic structure, free energy, and charge occupation, of the MnO(100) surface in the PM state with several OER intermediates, were reckoned and compared to those in the antiferromagnetic (AFM) state. We found that PM fluctuation enhances charge transfer from a surface Mn ion to each of the intermediates and strengthens the chemical bond between them, while not altering the overall features, such as the rate determining step and resting state, in reaction pathways. The enhanced charge transfer can be attributed to the delocalized nature of valence bands observed in the PM surface. In addition, it was observed that chemical-bond enhancement depends on the intermediates, resulting in significant deviations in reaction energy barriers. Our study suggests that PM fluctuations play a significant role in the thermochemistry of chemical reactions occurring on correlated oxide surfaces.
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Affiliation(s)
- Sangmoon Yoon
- Department of Materials Science and Engineering, Seoul National University, Seoul, 08826, Korea. and Department of Physics, Kyung Hee University, Seoul, 02447, Korea.
| | - Kyoungsuk Jin
- Department of Materials Science and Engineering, Seoul National University, Seoul, 08826, Korea.
| | - Sangmin Lee
- Department of Materials Science and Engineering, Seoul National University, Seoul, 08826, Korea.
| | - Ki Tae Nam
- Department of Materials Science and Engineering, Seoul National University, Seoul, 08826, Korea.
| | - Miyoung Kim
- Department of Materials Science and Engineering, Seoul National University, Seoul, 08826, Korea.
| | - Young-Kyun Kwon
- Department of Physics, Kyung Hee University, Seoul, 02447, Korea.
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13
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Wen T, Wang Y, Li C, Jiang D, Jiang Z, Qu S, Yang W, Wang Y. Site-Specific Pressure-Driven Spin-Crossover in Lu 1-xSc xFeO 3. J Phys Chem Lett 2020; 11:8549-8553. [PMID: 32970442 DOI: 10.1021/acs.jpclett.0c02537] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Pressure-driven spin-crossover (PSCO) is a collective quantum phenomenon frequently observed in transition-metal-based systems. According to the crystal-field theory, PSCO highly depends on the surrounding coordination environment of a given magnetic ion; nevertheless, it has never been verified experimentally up to now. Herein, we report the observation of a site-specific PSCO phenomenon in Lu1-xScxFeO3, in which octahedrally coordinated Fe3+ in orthorhombic LuFeO3 and trigonal-bipyramidally coordinated Fe3+ in hexagonal Lu0.5Sc0.5FeO3 show distinct PSCO response to external pressure. X-ray emission spectra and DFT calculations reveal the key role of coordination environment in a PSCO process and predict the occurrence of PSCO for trigonal-bipyramidally coordinated Fe3+ above 100 GPa, far beyond that of 50 GPa for octahedrally coordinated Fe3+ in LuFeO3. The demonstration of site-specific PSCO sheds light on the state-of-the-art design of PSCO materials for directional applications.
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Affiliation(s)
- Ting Wen
- Center for High Pressure Science and Technology Advanced Research (HPSTAR), Beijing 100094, China
| | - Yiming Wang
- Center for High Pressure Science and Technology Advanced Research (HPSTAR), Beijing 100094, China
| | - Chen Li
- Center for High Pressure Science and Technology Advanced Research (HPSTAR), Beijing 100094, China
| | - Dequan Jiang
- Center for High Pressure Science and Technology Advanced Research (HPSTAR), Beijing 100094, China
| | - Zimin Jiang
- Center for High Pressure Science and Technology Advanced Research (HPSTAR), Beijing 100094, China
| | - Shangqing Qu
- Center for High Pressure Science and Technology Advanced Research (HPSTAR), Beijing 100094, China
| | - Wenge Yang
- Center for High Pressure Science and Technology Advanced Research (HPSTAR), Beijing 100094, China
| | - Yonggang Wang
- Center for High Pressure Science and Technology Advanced Research (HPSTAR), Beijing 100094, China
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14
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Novoselov DY, Korotin DM, Shorikov AO, Oganov AR, Anisimov VI. Weak Coulomb correlations stabilize the electride high-pressure phase of elemental calcium. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:445501. [PMID: 32503018 DOI: 10.1088/1361-648x/ab99ed] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Accepted: 06/05/2020] [Indexed: 06/11/2023]
Abstract
Theoretical studies using the state-of-the-art density functional theory and dynamicalmean-field theory (DFT + DMFT) method show that weak electronic correlation effects are crucial for reproducing the experimentally observed pressure-induced phase transitions of calcium from β-tin toCmmmand then to the simple cubic structure. The formation of an electride state in calcium leads to the emergence of partially filled and localized electronic states under compression. The electride state was described using a basis containing molecular orbitals centered on the interstitial site and Ca-d states. We investigate the influence of Coulomb correlations on the structural properties of elemental Ca, noting that approaches based on the Hartree-Fock method (DFT +Uor hybrid functional schemes) are poorly suited for describing correlated metals. We find that only the DFT + DMFT method reproduces the correct sequence of high-pressure phase transitions of Ca at low temperatures.
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Affiliation(s)
- Dmitry Y Novoselov
- M.N. Miheev Institute of Metal Physics of Ural Branch of Russian Academy of Sciences-620108, Yekaterinburg, Russia
- Department of Theoretical Physics and Applied Mathematics, Ural Federal University, Mira St. 19, 620002 Yekaterinburg, Russia
- Skolkovo Institute of Science and Technology, 3 Nobel St., Moscow, 143026, Russia
| | - Dmitry M Korotin
- M.N. Miheev Institute of Metal Physics of Ural Branch of Russian Academy of Sciences-620108, Yekaterinburg, Russia
- Skolkovo Institute of Science and Technology, 3 Nobel St., Moscow, 143026, Russia
| | - Alexey O Shorikov
- M.N. Miheev Institute of Metal Physics of Ural Branch of Russian Academy of Sciences-620108, Yekaterinburg, Russia
- Department of Theoretical Physics and Applied Mathematics, Ural Federal University, Mira St. 19, 620002 Yekaterinburg, Russia
- Skolkovo Institute of Science and Technology, 3 Nobel St., Moscow, 143026, Russia
| | - Artem R Oganov
- Skolkovo Institute of Science and Technology, 3 Nobel St., Moscow, 143026, Russia
- Moscow Institute of Physics and Technology, 9 Institutskiy per., Dolgoprudny, Moscow Region, 141701, Russia
| | - Vladimir I Anisimov
- M.N. Miheev Institute of Metal Physics of Ural Branch of Russian Academy of Sciences-620108, Yekaterinburg, Russia
- Department of Theoretical Physics and Applied Mathematics, Ural Federal University, Mira St. 19, 620002 Yekaterinburg, Russia
- Skolkovo Institute of Science and Technology, 3 Nobel St., Moscow, 143026, Russia
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15
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Kashir A, Goian V, Yoon D, Cho BG, Jeong YH, Lee GH, Kamba S. Strain effect on magnetic-exchange-induced phonon splitting in NiO films. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:405607. [PMID: 32570228 DOI: 10.1088/1361-648x/ab9f08] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 06/22/2020] [Indexed: 06/11/2023]
Abstract
NiO thin films with various strains were grown on SrTiO3(STO) and MgO substrates using a pulsed laser deposition technique. The films were characterized using an x-ray diffraction, atomic force microscopy, and infrared reflectance spectroscopy. The films grown on STO (001) substrate show a compressive in-plane strain which increases as the film thickness is reduced resulting in an increase of the NiO phonon frequency. On the other hand, a tensile strain was detected in the NiO film grown on MgO (001) substrate which induces a softening of the phonon frequency. Overall, the variation of in-plane strain from -0.36% (compressive) to 0.48% (tensile) yields the decrease of the phonon frequency from 409.6 cm-1to 377.5 cm-1which occurs due to the ∼1% change of interatomic distances. The magnetic exchange-driven phonon splitting Δωin three different samples, with relaxed (i.e. zero) strain, 0.36% compressive strain and 0.48% tensile strain, was measured as a function of temperature. The Δωincreases on cooling in NiO relaxed film as in the previously published work on a bulk crystal. The splitting increases on cooling also in 0.48% tensile strained film, but Δωis systematically 3-4 cm-1smaller than in relaxed film. Since the phonon splitting is proportional to the non-dominant magnetic exchange interactionJ1, the reduction of phonon splitting in tensile-strained film was explained by a diminishing ofJ1with lattice expansion. Increase of Δωon cooling can be also explained by rising ofJ1with reduced temperature.
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Affiliation(s)
- Alireza Kashir
- Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Veronica Goian
- Institute of Physics, Czech Academy of Sciences, Na Slovance 2, 182 21 Prague 8, Czech Republic
| | - Daseob Yoon
- Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Byeong-Gwan Cho
- Pohang Accelerator Laboratory, Pohang, 37673, Republic of Korea
| | - Yoon Hee Jeong
- Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
- Department of Physics, Korea Advanced Institute of Science and Technology, Daejon, 34141, Republic of Korea
| | - Gil-Ho Lee
- Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Stanislav Kamba
- Institute of Physics, Czech Academy of Sciences, Na Slovance 2, 182 21 Prague 8, Czech Republic
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16
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Liu Z, Sakai Y, Yang J, Li W, Liu Y, Ye X, Qin S, Chen J, Agrestini S, Chen K, Liao SC, Haw SC, Baudelet F, Ishii H, Nishikubo T, Ishizaki H, Yamamoto T, Pan Z, Fukuda M, Ohashi K, Matsuno K, Machida A, Watanuki T, Kawaguchi SI, Arevalo-Lopez AM, Jin C, Hu Z, Attfield JP, Azuma M, Long Y. Sequential Spin State Transition and Intermetallic Charge Transfer in PbCoO 3. J Am Chem Soc 2020; 142:5731-5741. [PMID: 32083872 DOI: 10.1021/jacs.9b13508] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Spin state transitions and intermetallic charge transfers can essentially change material structural and physical properties while excluding external chemical doping. However, these two effects have rarely been found to occur sequentially in a specific material. In this article, we show the realization of these two phenomena in a perovskite oxide PbCoO3 with a simple ABO3 composition under high pressure. PbCoO3 possesses a peculiar A- and B-site ordered charge distribution Pb2+Pb4+3Co2+2Co3+2O12 with insulating behavior at ambient conditions. The high spin Co2+ gradually changes to low spin with increasing pressure up to about 15 GPa, leading to an anomalous increase of resistance magnitude. Between 15 and 30 GPa, the intermetallic charge transfer occurs between Pb4+ and Co2+ cations. The accumulated charge-transfer effect triggers a metal-insulator transition as well as a first-order structural phase transition toward a Tetra.-I phase at the onset of ∼20 GPa near room temperature. On further compression over 30 GPa, the charge transfer completes, giving rise to another first-order structural transformation toward a Tetra.-II phase and the reentrant electrical insulating behavior.
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Affiliation(s)
- Zhehong Liu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.,School of Physics, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yuki Sakai
- Kanagawa Institute of Industrial Science and Technology, 705-1 Shimoimaizumi, Ebina 243-0435, Japan.,Laboratory for Materials and Structures, Tokyo Institute of Technology, 4259 Nagatsuta, Midori, Yokohama 226-8503, Japan
| | - Junye Yang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Wenmin Li
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.,School of Physics, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ying Liu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.,School of Physics, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xubin Ye
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.,School of Physics, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shijun Qin
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.,School of Physics, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jinming Chen
- National Synchrotron Radiation Research Center, 101 Hsin-Ann Road, Hsinchu 30076, Taiwan, R.O.C
| | - Stefano Agrestini
- Max-Planck Institute for Chemical Physics of Solids, NöthnitzerStraße 40, 01187 Dresden, Germany
| | - Kai Chen
- Max-Planck Institute for Chemical Physics of Solids, NöthnitzerStraße 40, 01187 Dresden, Germany
| | - Sheng-Chieh Liao
- Max-Planck Institute for Chemical Physics of Solids, NöthnitzerStraße 40, 01187 Dresden, Germany
| | - Shu-Chih Haw
- National Synchrotron Radiation Research Center, 101 Hsin-Ann Road, Hsinchu 30076, Taiwan, R.O.C
| | - Francois Baudelet
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin-BP48, 91192 GIF-sur-Yvette Cedex, France
| | - Hirofumi Ishii
- National Synchrotron Radiation Research Center, 101 Hsin-Ann Road, Hsinchu 30076, Taiwan, R.O.C
| | - Takumi Nishikubo
- Laboratory for Materials and Structures, Tokyo Institute of Technology, 4259 Nagatsuta, Midori, Yokohama 226-8503, Japan
| | - Hayato Ishizaki
- Laboratory for Materials and Structures, Tokyo Institute of Technology, 4259 Nagatsuta, Midori, Yokohama 226-8503, Japan
| | - Tatsuru Yamamoto
- Laboratory for Materials and Structures, Tokyo Institute of Technology, 4259 Nagatsuta, Midori, Yokohama 226-8503, Japan
| | - Zhao Pan
- Laboratory for Materials and Structures, Tokyo Institute of Technology, 4259 Nagatsuta, Midori, Yokohama 226-8503, Japan
| | - Masayuki Fukuda
- Laboratory for Materials and Structures, Tokyo Institute of Technology, 4259 Nagatsuta, Midori, Yokohama 226-8503, Japan
| | - Kotaro Ohashi
- Laboratory for Materials and Structures, Tokyo Institute of Technology, 4259 Nagatsuta, Midori, Yokohama 226-8503, Japan
| | - Kana Matsuno
- Laboratory for Materials and Structures, Tokyo Institute of Technology, 4259 Nagatsuta, Midori, Yokohama 226-8503, Japan
| | - Akihiko Machida
- Quantum Beam Science Research Directorate, National Institutes for Quantum and Radiological Science and Technology, Sayo, Hyogo 679-5148, Japan
| | - Tetsu Watanuki
- Quantum Beam Science Research Directorate, National Institutes for Quantum and Radiological Science and Technology, Sayo, Hyogo 679-5148, Japan
| | - Saori I Kawaguchi
- Japan Synchrotron Radiation Research Institute, SPring-8, 1-1-1 Kouto, Sayo, Hyogo 679-5198, Japan
| | - Angel M Arevalo-Lopez
- Centre for Science at Extreme Conditions and School of Chemistry, University of Edinburgh, Mayfield Road, Edinburgh EH9 3JZ, United Kingdom
| | - Changqing Jin
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.,School of Physics, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhiwei Hu
- Max-Planck Institute for Chemical Physics of Solids, NöthnitzerStraße 40, 01187 Dresden, Germany
| | - J Paul Attfield
- Centre for Science at Extreme Conditions and School of Chemistry, University of Edinburgh, Mayfield Road, Edinburgh EH9 3JZ, United Kingdom
| | - Masaki Azuma
- Kanagawa Institute of Industrial Science and Technology, 705-1 Shimoimaizumi, Ebina 243-0435, Japan.,Laboratory for Materials and Structures, Tokyo Institute of Technology, 4259 Nagatsuta, Midori, Yokohama 226-8503, Japan
| | - Youwen Long
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.,School of Physics, University of Chinese Academy of Sciences, Beijing 100049, China.,Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
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17
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Rani S, Naresh G, Mandal TK. Coupled-substituted double-layer Aurivillius niobates: structures, magnetism and solar photocatalysis. Dalton Trans 2020; 49:1433-1445. [DOI: 10.1039/c9dt04339j] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Heterovalent coupled-substituted double-layer Aurivillius niobates, LaBi2Nb1.5M0.5O9 (M = Cr, Mn, Fe, Co), show interesting structural and magnetic characteristics in addition to sunlight-driven photocatalytic activity.
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Affiliation(s)
- Sonia Rani
- Department of Chemistry
- Indian Institute of Technology Roorkee
- Roorkee
- India
| | - Gollapally Naresh
- Department of Chemistry
- Indian Institute of Technology Roorkee
- Roorkee
- India
- Department of Chemical and Biological Engineering
| | - Tapas Kumar Mandal
- Department of Chemistry
- Indian Institute of Technology Roorkee
- Roorkee
- India
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18
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Kim HS, Haule K, Vanderbilt D. Mott Metal-Insulator Transitions in Pressurized Layered Trichalcogenides. PHYSICAL REVIEW LETTERS 2019; 123:236401. [PMID: 31868467 DOI: 10.1103/physrevlett.123.236401] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Revised: 09/17/2019] [Indexed: 06/10/2023]
Abstract
Transition metal phosphorous trichalcogenides, MPX_{3} (M and X being transition metal and chalcogen elements, respectively), have been the focus of substantial interest recently because they are unusual candidates undergoing Mott transition in the two-dimensional limit. Here we investigate material properties of the compounds with M=Mn and Ni employing ab initio density functional and dynamical mean-field calculations, especially their electronic behavior under external pressure in the paramagnetic phase. Mott metal-insulator transitions (MIT) are found to be a common feature for both compounds, but their lattice structures show drastically different behaviors depending on the relevant orbital degrees of freedom, i.e., t_{2g} or e_{g}. Under pressure, MnPS_{3} can undergo an isosymmetric structural transition within monoclinic space group by forming Mn-Mn dimers due to the strong direct overlap between the neighboring t_{2g} orbitals, accompanied by a significant volume collapse and a spin-state transition. In contrast, NiPS_{3} and NiPSe_{3}, with their active e_{g} orbital degrees of freedom, do not show a structural change at the MIT pressure or deep in the metallic phase within the monoclinic symmetry. Hence NiPS_{3} and NiPSe_{3} become rare examples of materials hosting electronic bandwidth-controlled Mott MITs, thus showing promise for ultrafast resistivity switching behavior.
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Affiliation(s)
- Heung-Sik Kim
- Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854-8019, USA
- Department of Physics, Kangwon National University, Chuncheon 24341, Korea
| | - Kristjan Haule
- Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854-8019, USA
| | - David Vanderbilt
- Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854-8019, USA
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19
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Yoon S, Kang SH, Lee S, Kim K, Song JP, Kim M, Kwon YK. A "non-dynamical" way of describing room-temperature paramagnetic manganese oxide. Phys Chem Chem Phys 2019; 21:15932-15939. [PMID: 31094381 DOI: 10.1039/c9cp00280d] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
We present a new approach based on static density functional theory (DFT) to describe paramagnetic manganese oxides, representative paramagnetic Mott insulators. We appended spin noncollinearity and a canonical ensemble to the magnetic sampling method (MSM), which is one of the supercell approaches based on the disordered local moment model. The combination of the noncollinear MSM (NCMSM) with DFT+U represents a highly favorable computational method called NCMSM+U to accurately determine the paramagnetic properties of MnO with moderate numerical cost. The effects of electron correlations and spin noncollinearity on the properties of MnO were also investigated. We found that the spin noncollinearity plays an important role in determining the detailed electronic profile and precise energetics of paramagnetic MnO. Our results illustrate that the NCMSM+U approach may be used for insulating materials as an alternative to the ab initio framework of dynamic mean field theory based on DFT in the simulation of the room-temperature paramagnetic properties.
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Affiliation(s)
- Sangmoon Yoon
- Department of Materials Science and Engineering, Seoul National University, Seoul, 08826, Korea.
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20
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21
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Wang Y, Ying J, Zhou Z, Sun J, Wen T, Zhou Y, Li N, Zhang Q, Han F, Xiao Y, Chow P, Yang W, Struzhkin VV, Zhao Y, Mao HK. Emergent superconductivity in an iron-based honeycomb lattice initiated by pressure-driven spin-crossover. Nat Commun 2018; 9:1914. [PMID: 29765049 PMCID: PMC5953925 DOI: 10.1038/s41467-018-04326-1] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2017] [Accepted: 04/19/2018] [Indexed: 11/09/2022] Open
Abstract
The discovery of iron-based superconductors (FeSCs), with the highest transition temperature (Tc) up to 55 K, has attracted worldwide research efforts over the past ten years. So far, all these FeSCs structurally adopt FeSe-type layers with a square iron lattice and superconductivity can be generated by either chemical doping or external pressure. Herein, we report the observation of superconductivity in an iron-based honeycomb lattice via pressure-driven spin-crossover. Under compression, the layered FePX3 (X = S, Se) simultaneously undergo large in-plane lattice collapses, abrupt spin-crossovers, and insulator-metal transitions. Superconductivity emerges in FePSe3 along with the structural transition and vanishing of magnetic moment with a starting Tc ~ 2.5 K at 9.0 GPa and the maximum Tc ~ 5.5 K around 30 GPa. The discovery of superconductivity in iron-based honeycomb lattice provides a demonstration for the pursuit of transition-metal-based superconductors via pressure-driven spin-crossover.
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Affiliation(s)
- Yonggang Wang
- Center for High Pressure Science and Technology Advanced Research (HPSTAR), 100094, Beijing, China.,HPSynC, Geophysical Laboratory, Carnegie Institution of Washington, Argonne, IL, 60439, USA
| | - Jianjun Ying
- Geophysical Laboratory, Carnegie Institution of Washington, Washington, DC, 20015, USA.,HPCAT, Geophysical Laboratory, Carnegie Institution of Washington, Argonne, IL, 60439, USA
| | - Zhengyang Zhou
- College of Chemistry and Molecular Engineering, Peking University, 100871, Beijing, China.,College of Chemistry and Chemical Engineering, Chongqing University, 400044, Chongqing, China
| | - Junliang Sun
- College of Chemistry and Molecular Engineering, Peking University, 100871, Beijing, China
| | - Ting Wen
- Center for High Pressure Science and Technology Advanced Research (HPSTAR), 100094, Beijing, China
| | - Yannan Zhou
- Institute of Nanostructured Functional Materials, Huanghe Science and Technology College, 450006, Zhengzhou, China
| | - Nana Li
- Center for High Pressure Science and Technology Advanced Research (HPSTAR), 100094, Beijing, China
| | - Qian Zhang
- Center for High Pressure Science and Technology Advanced Research (HPSTAR), 100094, Beijing, China
| | - Fei Han
- Center for High Pressure Science and Technology Advanced Research (HPSTAR), 100094, Beijing, China.,HPSynC, Geophysical Laboratory, Carnegie Institution of Washington, Argonne, IL, 60439, USA
| | - Yuming Xiao
- HPCAT, Geophysical Laboratory, Carnegie Institution of Washington, Argonne, IL, 60439, USA
| | - Paul Chow
- HPCAT, Geophysical Laboratory, Carnegie Institution of Washington, Argonne, IL, 60439, USA
| | - Wenge Yang
- Center for High Pressure Science and Technology Advanced Research (HPSTAR), 100094, Beijing, China. .,HPSynC, Geophysical Laboratory, Carnegie Institution of Washington, Argonne, IL, 60439, USA.
| | - Viktor V Struzhkin
- Geophysical Laboratory, Carnegie Institution of Washington, Washington, DC, 20015, USA.
| | - Yusheng Zhao
- Southern University of Science and Technology, 518055, Shenzhen, China.
| | - Ho-Kwang Mao
- Center for High Pressure Science and Technology Advanced Research (HPSTAR), 100094, Beijing, China.,Geophysical Laboratory, Carnegie Institution of Washington, Washington, DC, 20015, USA
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22
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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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23
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Pressure-induced magnetic moment abnormal increase in Mn 2FeAl and non-continuing decrease in Fe 2MnAl via first principles. Sci Rep 2017; 7:16522. [PMID: 29184102 PMCID: PMC5705647 DOI: 10.1038/s41598-017-16735-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 11/16/2017] [Indexed: 11/30/2022] Open
Abstract
The magnetism of Fe2MnAl and Mn2FeAl compounds are studied by first principles. Evolutions of magnetic moment of Fe2MnAl display distinct variation trends under pressure, showing three different slopes at different pressure intervals, 0~100 GPa, 100~250 GPa, 250–400 GPa, respectively, and the moment collapses finally at 450 GPa. The magnetic moment of Mn2FeAl shows an increasing tendency below 40 GPa and decreases subsequently with pressure, and collapses ultimately at about 175 GPa. Such non-continuing decrease of Fe2MnAl originates from the unusual charge transfer of Fe and Mn and bond populations rearrangement of Fe-Fe and Mn-Fe, whereas the distinct moment evolution of Mn2FeAl is attributed to the complicated distributions of bond populations. The half-metallicity of the compounds can be maintained at low pressure, below about 100 GPa in Fe2MnAl and 50 GPa in Mn2FeAl. The magnetic moment collapse process didn’t induce volume and bond length anomalies in the two compounds, the unique anomaly is the elastic softening behaviour in elastic constant c44 and shear (G) and Young’s (E) moduli of Fe2MnAl at 270 GPa, where the second moment collapse occurs.
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24
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Baranov AI, Martín Pendás Á. Electron sharing and localization in real space for the Mott transition from 1RDMFT periodic calculations. Theor Chem Acc 2017. [DOI: 10.1007/s00214-017-2125-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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25
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Musfeldt JL, O'Neal KR, Brinzari TV, Chen P, Schlueter JA, Manson JL, Litvinchuk AP, Liu Z. Pressure-Temperature Phase Diagram Reveals Spin-Lattice Interactions in Co[N(CN) 2] 2. Inorg Chem 2017; 56:4950-4955. [PMID: 28414436 DOI: 10.1021/acs.inorgchem.6b03097] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Diamond anvil cell techniques, synchrotron-based infrared and Raman spectroscopies, and lattice dynamics calculations are combined with prior magnetic property work to reveal the pressure-temperature phase diagram of Co[N(CN)2]2. The second-order structural boundaries converge on key areas of activity involving the spin state exposing how the pressure-induced local lattice distortions trigger the ferromagnetic → antiferromagnetic transition in this quantum material.
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Affiliation(s)
- J L Musfeldt
- Department of Chemistry, University of Tennessee , Knoxville, Tennessee 37996, United States
| | - K R O'Neal
- Department of Chemistry, University of Tennessee , Knoxville, Tennessee 37996, United States
| | - T V Brinzari
- Department of Chemistry, University of Tennessee , Knoxville, Tennessee 37996, United States
| | - P Chen
- Department of Chemistry, University of Tennessee , Knoxville, Tennessee 37996, United States
| | - J A Schlueter
- Division of Materials Research, National Science Foundation , Arlington, Virginia 22230, United States
| | - J L Manson
- Department of Chemistry and Biochemistry, Eastern Washington University , Cheney, Washington 99004, United States
| | - A P Litvinchuk
- Texas Center for Superconductivity and Department of Physics, University of Houston , Houston, Texas 77204, United States
| | - Z Liu
- Geophysical Laboratory, Carnegie Institution of Washington , Washington, D.C. 20015, United States
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26
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Wang Y, Zhou Z, Wen T, Zhou Y, Li N, Han F, Xiao Y, Chow P, Sun J, Pravica M, Cornelius AL, Yang W, Zhao Y. Pressure-Driven Cooperative Spin-Crossover, Large-Volume Collapse, and Semiconductor-to-Metal Transition in Manganese(II) Honeycomb Lattices. J Am Chem Soc 2016; 138:15751-15757. [PMID: 27934025 DOI: 10.1021/jacs.6b10225] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Spin-crossover (SCO) is generally regarded as a spectacular molecular magnetism in 3d4-3d7 metal complexes and holds great promise for various applications such as memory, displays, and sensors. In particular, SCO materials can be multifunctional when a classical light- or temperature-induced SCO occurs along with other cooperative structural and/or electrical transport alterations. However, such a cooperative SCO has rarely been observed in condensed matter under hydrostatic pressure (an alternative external stimulus to light or temperature), probably due to the lack of synergy between metal neighbors under compression. Here, we report the observation of a pressure-driven, cooperative SCO in the two-dimensional (2D) honeycomb antiferromagnets MnPS3 and MnPSe3 at room temperature. Applying pressure to this confined 2D system leads to a dramatic magnetic moment collapse of Mn2+ (d5) from S = 5/2 to S = 1/2. Significantly, a number of collective phenomena were observed along with the SCO, including a large lattice collapse (∼20% in volume), the formation of metallic bonding, and a semiconductor-to-metal transition. Experimental evidence shows that all of these events occur in the honeycomb lattice, indicating a strongly cooperative mechanism that facilitates the occurrence of the abrupt pressure-driven SCO. We believe that the observation of this cooperative pressure-driven SCO in a 2D system can provide a rare model for theoretical investigations and lead to the discovery of more pressure-responsive multifunctional materials.
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Affiliation(s)
- Yonggang Wang
- High Pressure Science and Engineering Center, University of Nevada , Las Vegas, Nevada 89154, United States.,HPSynC, Geophysical Laboratory, Carnegie Institution of Washington , Argonne, Illinois 60439, United States
| | - Zhengyang Zhou
- College of Chemistry and Molecular Engineering, Peking University , Beijing 100871, China.,College of Chemistry and Chemical Engineering, Chongqing University , Chongqing 400044, China
| | - Ting Wen
- Institute of Nanostructured Functional Materials, Huanghe Science and Technology College , Zhengzhou, Henan 450006, China
| | - Yannan Zhou
- Institute of Nanostructured Functional Materials, Huanghe Science and Technology College , Zhengzhou, Henan 450006, China
| | - Nana Li
- Center for High Pressure Science and Technology Advanced Research (HPSTAR) , Pudong, Shanghai 201203, China
| | - Fei Han
- HPSynC, Geophysical Laboratory, Carnegie Institution of Washington , Argonne, Illinois 60439, United States.,Center for High Pressure Science and Technology Advanced Research (HPSTAR) , Pudong, Shanghai 201203, China.,Center for the Study of Matter at Extreme Conditions, Department of Mechanical and Materials Engineering, Florida International University , Miami, Florida 33199, United States
| | - Yuming Xiao
- High Pressure Collaborative Access Team (HPCAT), Geophysical Laboratory, Carnegie Institution of Washington , Argonne, Illinois 60439, United States
| | - Paul Chow
- High Pressure Collaborative Access Team (HPCAT), Geophysical Laboratory, Carnegie Institution of Washington , Argonne, Illinois 60439, United States
| | - Junliang Sun
- College of Chemistry and Molecular Engineering, Peking University , Beijing 100871, China
| | - Michael Pravica
- High Pressure Science and Engineering Center, University of Nevada , Las Vegas, Nevada 89154, United States
| | - Andrew L Cornelius
- High Pressure Science and Engineering Center, University of Nevada , Las Vegas, Nevada 89154, United States
| | - Wenge Yang
- HPSynC, Geophysical Laboratory, Carnegie Institution of Washington , Argonne, Illinois 60439, United States.,Center for High Pressure Science and Technology Advanced Research (HPSTAR) , Pudong, Shanghai 201203, China
| | - Yusheng Zhao
- High Pressure Science and Engineering Center, University of Nevada , Las Vegas, Nevada 89154, United States.,Southern University of Science and Technology , Shenzhen 518055, China
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27
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Wang Y, Bai L, Wen T, Yang L, Gou H, Xiao Y, Chow P, Pravica M, Yang W, Zhao Y. Giant Pressure‐Driven Lattice Collapse Coupled with Intermetallic Bonding and Spin‐State Transition in Manganese Chalcogenides. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201605410] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Yonggang Wang
- High Pressure Science and Engineering Center University of Nevada Las Vegas Las Vegas NV 89154 USA
- High Pressure Synergetic Consortium (HPSynC), Geophysical Laboratory Carnegie Institution of Washington Argonne IL 60439 USA
| | - Ligang Bai
- High Pressure Collaborative Access Team (HPCAT) Geophysical Laboratory Carnegie Institution of Washington Argonne IL 60439 USA
| | - Ting Wen
- Institute of Nanostructured Functional Materials Huanghe Science and Technology College Zhengzhou Henan 450006 China
| | - Liuxiang Yang
- High Pressure Synergetic Consortium (HPSynC), Geophysical Laboratory Carnegie Institution of Washington Argonne IL 60439 USA
- Center for High Pressure Science and Technology Advanced Research (HPSTAR) Shanghai 201203 China
| | - Huiyang Gou
- Center for High Pressure Science and Technology Advanced Research (HPSTAR) Shanghai 201203 China
| | - Yuming Xiao
- High Pressure Collaborative Access Team (HPCAT) Geophysical Laboratory Carnegie Institution of Washington Argonne IL 60439 USA
| | - Paul Chow
- High Pressure Collaborative Access Team (HPCAT) Geophysical Laboratory Carnegie Institution of Washington Argonne IL 60439 USA
| | - Michael Pravica
- High Pressure Science and Engineering Center University of Nevada Las Vegas Las Vegas NV 89154 USA
| | - Wenge Yang
- High Pressure Synergetic Consortium (HPSynC), Geophysical Laboratory Carnegie Institution of Washington Argonne IL 60439 USA
- Center for High Pressure Science and Technology Advanced Research (HPSTAR) Shanghai 201203 China
| | - Yusheng Zhao
- High Pressure Science and Engineering Center University of Nevada Las Vegas Las Vegas NV 89154 USA
- Southern University of Science and Technology Shenzhen 518055 China
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28
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Wang Y, Bai L, Wen T, Yang L, Gou H, Xiao Y, Chow P, Pravica M, Yang W, Zhao Y. Giant Pressure‐Driven Lattice Collapse Coupled with Intermetallic Bonding and Spin‐State Transition in Manganese Chalcogenides. Angew Chem Int Ed Engl 2016; 55:10350-3. [DOI: 10.1002/anie.201605410] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Indexed: 11/12/2022]
Affiliation(s)
- Yonggang Wang
- High Pressure Science and Engineering Center University of Nevada Las Vegas Las Vegas NV 89154 USA
- High Pressure Synergetic Consortium (HPSynC), Geophysical Laboratory Carnegie Institution of Washington Argonne IL 60439 USA
| | - Ligang Bai
- High Pressure Collaborative Access Team (HPCAT) Geophysical Laboratory Carnegie Institution of Washington Argonne IL 60439 USA
| | - Ting Wen
- Institute of Nanostructured Functional Materials Huanghe Science and Technology College Zhengzhou Henan 450006 China
| | - Liuxiang Yang
- High Pressure Synergetic Consortium (HPSynC), Geophysical Laboratory Carnegie Institution of Washington Argonne IL 60439 USA
- Center for High Pressure Science and Technology Advanced Research (HPSTAR) Shanghai 201203 China
| | - Huiyang Gou
- Center for High Pressure Science and Technology Advanced Research (HPSTAR) Shanghai 201203 China
| | - Yuming Xiao
- High Pressure Collaborative Access Team (HPCAT) Geophysical Laboratory Carnegie Institution of Washington Argonne IL 60439 USA
| | - Paul Chow
- High Pressure Collaborative Access Team (HPCAT) Geophysical Laboratory Carnegie Institution of Washington Argonne IL 60439 USA
| | - Michael Pravica
- High Pressure Science and Engineering Center University of Nevada Las Vegas Las Vegas NV 89154 USA
| | - Wenge Yang
- High Pressure Synergetic Consortium (HPSynC), Geophysical Laboratory Carnegie Institution of Washington Argonne IL 60439 USA
- Center for High Pressure Science and Technology Advanced Research (HPSTAR) Shanghai 201203 China
| | - Yusheng Zhao
- High Pressure Science and Engineering Center University of Nevada Las Vegas Las Vegas NV 89154 USA
- Southern University of Science and Technology Shenzhen 518055 China
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29
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Korotin DM, Anisimov VI, Streltsov SV. Pressure-induced magnetic transitions with change of the orbital configuration in dimerised systems. Sci Rep 2016; 6:25831. [PMID: 27189206 PMCID: PMC4870518 DOI: 10.1038/srep25831] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Accepted: 04/22/2016] [Indexed: 11/10/2022] Open
Abstract
We suggest a possible scenario for magnetic transition under pressure in dimerised systems where electrons are localised on molecular orbitals. The mechanism of transition is not related with competition between kinetic energy and on-site Coulomb repulsion as in Mott-Hubbard systems, or between crystal-field splitting and intra-atomic exchange as in classical atomic spin-state transitions. Instead, it is driven by the change of bonding-antibonding splitting on part of the molecular orbitals. In the magnetic systems with few half-filled molecular orbitals external pressure may result in increase of the bonding-antibonding splitting and localise all electrons on low-lying molecular orbitals suppressing net magnetic moment of the system. We give examples of the systems, where this or inverse transition may occur and by means of ab initio band structure calculations predict that it can be observed in α−MoCl4 at pressure P ~ 11 GPa.
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Affiliation(s)
- Dmitry M Korotin
- Institute of Metal Physics, S. Kovalevskoy St. 18, 620990 Yekaterinburg, Russia
| | - Vladimir I Anisimov
- Institute of Metal Physics, S. Kovalevskoy St. 18, 620990 Yekaterinburg, Russia.,Department of theoretical physics and applied mathematics, Ural Federal University, Mira St. 19, 620002 Yekaterinburg, Russia
| | - Sergey V Streltsov
- Institute of Metal Physics, S. Kovalevskoy St. 18, 620990 Yekaterinburg, Russia.,Department of theoretical physics and applied mathematics, Ural Federal University, Mira St. 19, 620002 Yekaterinburg, Russia
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30
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Chen Z, Li J. A new method applicable to study solid compounds with multiple polyhedral structures. J Comput Chem 2016; 37:1476-83. [DOI: 10.1002/jcc.24360] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Revised: 02/16/2016] [Accepted: 02/22/2016] [Indexed: 11/09/2022]
Affiliation(s)
- Zhenlian Chen
- Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences; Ningbo 315201 People's Republic of China
| | - Jun Li
- Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences; Ningbo 315201 People's Republic of China
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31
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Abstract
The Mott insulator in correlated electron systems arises from classical Coulomb repulsion between carriers to provide a powerful force for electron localization. Turning such an insulator into a metal, the so-called Mott transition, is commonly achieved by "bandwidth" control or "band filling." However, both mechanisms deviate from the original concept of Mott, which attributes such a transition to the screening of Coulomb potential and associated lattice contraction. Here, we report a pressure-induced isostructural Mott transition in cubic perovskite PbCrO3. At the transition pressure of ∼3 GPa, PbCrO3 exhibits significant collapse in both lattice volume and Coulomb potential. Concurrent with the collapse, it transforms from a hybrid multiferroic insulator to a metal. For the first time to our knowledge, these findings validate the scenario conceived by Mott. Close to the Mott criticality at ∼300 K, fluctuations of the lattice and charge give rise to elastic anomalies and Laudau critical behaviors resembling the classic liquid-gas transition. The anomalously large lattice volume and Coulomb potential in the low-pressure insulating phase are largely associated with the ferroelectric distortion, which is substantially suppressed at high pressures, leading to the first-order phase transition without symmetry breaking.
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32
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Shinohara Y, Sharma S, Shallcross S, Lathiotakis NN, Gross EKU. Spectrum for Nonmagnetic Mott Insulators from Power Functional within Reduced Density Matrix Functional Theory. J Chem Theory Comput 2015; 11:4895-9. [DOI: 10.1021/acs.jctc.5b00661] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Y. Shinohara
- Max-Planck-Institut
für Mikrostrukturphysik, Weinberg
2, D-06120 Halle, Saxony-Anhalt, Germany
| | - S. Sharma
- Max-Planck-Institut
für Mikrostrukturphysik, Weinberg
2, D-06120 Halle, Saxony-Anhalt, Germany
- Department
of Physics, Indian Institute of Technology, Roorkee, 247667 Uttarkhand, India
| | - S. Shallcross
- Lehrstuhl für
Theoretische Festkörperphysik, Staudstrasse 7-B2, 91058 Erlangen, Bavaria, Germany
| | - N. N. Lathiotakis
- Max-Planck-Institut
für Mikrostrukturphysik, Weinberg
2, D-06120 Halle, Saxony-Anhalt, Germany
- Theoretical and
Physical Chemistry Institute, National Hellenic Research Foundation, Vass. Constantinou 48, GR-11635 Athens, Greece
| | - E. K. U. Gross
- Max-Planck-Institut
für Mikrostrukturphysik, Weinberg
2, D-06120 Halle, Saxony-Anhalt, Germany
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33
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Skorikov NA, Shorikov AO, Skornyakov SL, Korotin MA, Anisimov VI. Mechanism of magnetic moment collapse under pressure in ferropericlase. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2015; 27:275501. [PMID: 26086296 DOI: 10.1088/0953-8984/27/27/275501] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We propose a new scenario for the magnetic collapse under pressure in ferropericlase (FP) (Fe(1/4)Mg(3/4))O without the presence of intermediate spin state, which contradicts the mechanism proposed in (2013 Phys. Rev. B 87 165113). This scenario is supported by results of combined local density approximation + dynamical mean-field theory method calculations for the paramagnetic phase at ambient and high pressures. At ambient pressure, calculation gave (Fe(1/4)Mg(3/4))O as an insulator with Fe 3d-shell in high-spin state. Experimentally observed high-spin to low-spin state transition of the Fe(2+) ion in the pressure range of 35-75 GPa is successfully reproduced in our calculations. The spin crossover is characterized by coexistence of Fe(2+) ions in high and low spin state but intermediate spin state is absent in the whole pressure range. Moreover, the probability of Fe ion d(7) onfiguration with S = 1 grows with pressure due to shortening of metal-oxygen distance. Also, no metal-insulator transition was obtained up to the pressure 140 GPa in agreement with experiment.
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Affiliation(s)
- N A Skorikov
- M.N. Miheev Institute of Metal Physics of Ural Branch of Russian Academy of Sciences, 620137 Yekaterinburg, Russia
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34
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Leonov I, Anisimov VI, Vollhardt D. First-principles calculation of atomic forces and structural distortions in strongly correlated materials. PHYSICAL REVIEW LETTERS 2014; 112:146401. [PMID: 24765993 DOI: 10.1103/physrevlett.112.146401] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2013] [Indexed: 06/03/2023]
Abstract
We introduce a novel computational approach for the investigation of complex correlated electron materials which makes it possible to evaluate interatomic forces and, thereby, determine atomic displacements and structural transformations induced by electronic correlations. It combines ab initio band structure and dynamical mean-field theory and is implemented with the linear-response formalism regarding atomic displacements. We apply this new technique to explore structural transitions of prototypical correlated systems such as elemental hydrogen, SrVO3, and KCuF3.
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Affiliation(s)
- I Leonov
- Theoretical Physics III, Center for Electronic Correlations and Magnetism, Institute of Physics, University of Augsburg, 86135 Augsburg, Germany
| | - V I Anisimov
- Institute of Metal Physics, S. Kovalevskaya Street 18, 620219, Yekaterinburg GSP-170, Russia and Ural Federal University, 620002 Yekaterinburg, Russia
| | - D Vollhardt
- Theoretical Physics III, Center for Electronic Correlations and Magnetism, Institute of Physics, University of Augsburg, 86135 Augsburg, Germany
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35
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Abstract
Dramatic volume collapses under pressure are fundamental to geochemistry and of increasing importance to fields as diverse as hydrogen storage and high-temperature superconductivity. In transition metal materials, collapses are usually driven by so-called spin-state transitions, the interplay between the single-ion crystal field and the size of the magnetic moment. Here we show that the classical S = 5/2 mineral hauerite (MnS2) undergoes an unprecedented (ΔV ~ 22%) collapse driven by a conceptually different magnetic mechanism. Using synchrotron X-ray diffraction we show that cold compression induces the formation of a disordered intermediate. However, using an evolutionary algorithm we predict a new structure with edge-sharing chains. This is confirmed as the thermodynamic ground state using in situ laser heating. We show that magnetism is globally absent in the new phase, as low-spin quantum S = 1/2 moments are quenched by dimerization. Our results show how the emergence of metal-metal bonding can stabilize giant spin-lattice coupling in Earth's minerals.
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36
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Anisimov VI, Lukoyanov AV. Investigation of real materials with strong electronic correlations by the LDA+DMFT method. Acta Crystallogr C Struct Chem 2014; 70:137-59. [PMID: 24508959 DOI: 10.1107/s2053229613032312] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Accepted: 11/20/2013] [Indexed: 11/10/2022] Open
Abstract
Materials with strong electronic correlations are at the cutting edge of experimental and theoretical studies, capturing the attention of researchers for a great variety of interesting phenomena: metal-insulator, phase and magnetic spin transitions, `heavy fermion' systems, interplay between magnetic order and superconductivity, appearance and disappearance of local magnetic moments, and transport property anomalies. It is clear that the richness of physical phenomena for these compounds is a result of partially filled 3d, 4f or 5f electron shells with local magnetic moments preserved in the solid state. Strong interactions of d and f electrons with each other and with itinerant electronic states of the material are responsible for its anomalous properties. Electronic structure calculations for strongly correlated materials should explicitly take into account Coulombic interactions between d or f electrons. Recent advances in this field are related to the development of the LDA+DMFT method, which combines local density approximation (LDA) with dynamical mean-field theory (DMFT) to account for electronic correlation effects. In recent years, LDA+DMFT has allowed the successful treatment not only of simple systems but also of complicated real compounds. Nowadays, the LDA+DMFT method is the state-of-the-art tool for investigating correlated metals and insulators, spin and metal-insulator transitions (MIT) in transition-metal compounds in paramagnetic and magnetically ordered phases.
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Affiliation(s)
- V I Anisimov
- Institute of Metal Physics, Russian Academy of Sciences, 620990 Yekaterinburg, Russia
| | - A V Lukoyanov
- Institute of Metal Physics, Russian Academy of Sciences, 620990 Yekaterinburg, Russia
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37
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Manghi F. Multi-orbital cluster perturbation theory for transition metal oxides. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2014; 26:015602. [PMID: 24292335 DOI: 10.1088/0953-8984/26/1/015602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We present an extension of cluster perturbation theory to include many-body correlations associated with local e-e repulsion in real materials. We show that this approach can describe the physics of complex correlated materials where different atomic species and different orbitals coexist. The prototypical case of MnO is considered.
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Affiliation(s)
- F Manghi
- Dipartimento di Fisica, Università di Modena e Reggio Emilia and CNR, Institute of NanoSciences-S3, Via Campi 213/A, I-41125 Modena, Italy
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38
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Ming X, Meng X, Xu QL, Du F, Wei YJ, Chen G. Uniaxial pressure induced phase transitions in multiferroic materials BiCoO3. RSC Adv 2014. [DOI: 10.1039/c4ra11408f] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The crystallographic structure stability, spin state and electronic structure variation in tetragonal multiferroic material BiCoO3under uniaxial pressure are investigated by means of first-principles density functional theory calculations.
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Affiliation(s)
- Xing Ming
- College of Physics and Electronic Information
- Huanggang Normal University
- Huanggang 438000, P. R. China
- Key Laboratory of Physics and Technology for Advanced Batteries (Ministry of Education) and College of Physics
- Jilin University
| | - Xing Meng
- Key Laboratory of Physics and Technology for Advanced Batteries (Ministry of Education) and College of Physics
- Jilin University
- Changchun 130012, P. R. China
| | - Qiao-Ling Xu
- Key Laboratory of Physics and Technology for Advanced Batteries (Ministry of Education) and College of Physics
- Jilin University
- Changchun 130012, P. R. China
| | - Fei Du
- Key Laboratory of Physics and Technology for Advanced Batteries (Ministry of Education) and College of Physics
- Jilin University
- Changchun 130012, P. R. China
| | - Ying-Jin Wei
- Key Laboratory of Physics and Technology for Advanced Batteries (Ministry of Education) and College of Physics
- Jilin University
- Changchun 130012, P. R. China
| | - Gang Chen
- Key Laboratory of Physics and Technology for Advanced Batteries (Ministry of Education) and College of Physics
- Jilin University
- Changchun 130012, P. R. China
- State Key Laboratory of Superhard Materials and College of Physics
- Jilin University
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39
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Sharma S, Dewhurst JK, Shallcross S, Gross EKU. Spectral density and metal-insulator phase transition in Mott insulators within reduced density matrix functional theory. PHYSICAL REVIEW LETTERS 2013; 110:116403. [PMID: 25166559 DOI: 10.1103/physrevlett.110.116403] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2012] [Revised: 02/08/2013] [Indexed: 05/11/2023]
Abstract
We present a method for calculating the spectrum of periodic solids within reduced density matrix functional theory. This method is validated by a detailed comparison of the angular momentum projected spectral density with that of well-established many-body techniques, finding very good agreement in all cases. The physics behind the pressure induced insulator-metal phase transition in MnO is investigated. The driving mechanism of this transition is identified as increased crystal field splitting with pressure, resulting in a charge redistribution between the Mn e(g) and t(2)g symmetry projected states.
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Affiliation(s)
- S Sharma
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany
| | - J K Dewhurst
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany
| | - S Shallcross
- Lehrstuhl für Theoretische Festkörperphysik, Staudstrasse 7-B2, 91058 Erlangen, Germany
| | - E K U Gross
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany
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40
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Thunström P, Di Marco I, Eriksson O. Electronic entanglement in late transition metal oxides. PHYSICAL REVIEW LETTERS 2012; 109:186401. [PMID: 23215301 DOI: 10.1103/physrevlett.109.186401] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Indexed: 06/01/2023]
Abstract
We present a study of the entanglement in the electronic structure of the late transition metal monoxides--MnO, FeO, CoO, and NiO--obtained by means of density-functional theory in the local density approximation combined with dynamical mean-field theory. The impurity problem is solved through exact diagonalization, which grants full access to the thermally mixed many-body ground state density operator. The quality of the electronic structure is affirmed through a direct comparison between the calculated electronic excitation spectrum and photoemission experiments. Our treatment allows for a quantitative investigation of the entanglement in the electronic structure. Two main sources of entanglement are explicitly resolved through the use of a fidelity based geometrical entanglement measure, and additional information is gained from a complementary entropic entanglement measure. We show that the interplay of crystal field effects and Coulomb interaction causes the entanglement in CoO to take a particularly intricate form.
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Affiliation(s)
- Patrik Thunström
- Department of Physics and Astronomy, Uppsala University, Box 516, SE-75120 Uppsala, Sweden
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41
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Gavriliuk AG, Trojan IA, Struzhkin VV. Insulator-metal transition in highly compressed NiO. PHYSICAL REVIEW LETTERS 2012; 109:086402. [PMID: 23002762 DOI: 10.1103/physrevlett.109.086402] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2012] [Indexed: 06/01/2023]
Abstract
The insulator-metal transition was observed experimentally in nickel monoxide (NiO) at very high pressures of ~240 GPa. The sample resistance becomes measurable at about 130 GPa and decreases substantially with the pressure increase to ~240 GPa. A sharp drop in resistance by about 3 orders of magnitude has been observed at ~240 GPa with a concomitant change of the resistance type from semiconducting to metallic. This is the first experimental observation of an insulator-metal transition in NiO, which was anticipated by Mott decades ago. From simple multielectron consideration, the metallic phase of NiO forms when the effective Hubbard energy U(eff) is almost equal to the estimated full bandwidth 2W.
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Affiliation(s)
- Alexander G Gavriliuk
- Geophysical Laboratory, Carnegie Institution of Washington, Washington, DC 20015, USA
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42
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Kant C, Schmidt M, Wang Z, Mayr F, Tsurkan V, Deisenhofer J, Loidl A. Universal exchange-driven phonon splitting in antiferromagnets. PHYSICAL REVIEW LETTERS 2012; 108:177203. [PMID: 22680902 DOI: 10.1103/physrevlett.108.177203] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2011] [Indexed: 06/01/2023]
Abstract
We report a linear dependence of the phonon splitting Δω on the nondominant exchange coupling constant J(nd) in the antiferromagnetic transition-metal monoxides MnO, FeO, CoO, NiO, and in the frustrated antiferromagnetic oxide spinels CdCr(2)O(4), MgCr(2)O(4), and ZnCr(2)O(4). It directly confirms the theoretical prediction of an exchange-induced splitting of the zone-center optical phonon for the monoxides and explains the magnitude and the change of sign of the phonon splitting on changing the sign of the nondominant exchange also in the frustrated oxide spinels. The experimentally found linear relation [symbol:see text}Δω=βJ(nd)S(2) with slope β=3.7 describes the splitting for both systems and agrees with the observations in the antiferromagnets KCoF(3) and KNiF(3) with perovskite structure and negligible next-nearest neighbor coupling. The common behavior found for very different classes of cubic antiferromagnets suggests a universal dependence of the exchange-induced phonon splitting at the antiferromagnetic transition on the nondominant exchange coupling.
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Affiliation(s)
- Ch Kant
- Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, 86135 Augsburg, Germany
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43
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Byczuk K, Kuneš J, Hofstetter W, Vollhardt D. Quantification of correlations in quantum many-particle systems. PHYSICAL REVIEW LETTERS 2012; 108:087004. [PMID: 22463560 DOI: 10.1103/physrevlett.108.087004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2011] [Indexed: 05/31/2023]
Abstract
We introduce a well-defined and unbiased measure of the strength of correlations in quantum many-particle systems which is based on the relative von Neumann entropy computed from the density operator of correlated and uncorrelated states. The usefulness of this general concept is demonstrated by quantifying correlations of interacting electrons in the Hubbard model and in a series of transition-metal oxides using dynamical mean-field theory.
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Affiliation(s)
- Krzysztof Byczuk
- Physics Faculty, Institute of Theoretical Physics, University of Warsaw, Warszawa, Poland
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Zhang YZ, Opahle I, Jeschke HO, Valentí R. Pressure-driven phase transitions in TiOCl and the family (Ca, Sr, Ba)Fe2As2. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2010; 22:164208. [PMID: 21386414 DOI: 10.1088/0953-8984/22/16/164208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Motivated by recent experimental measurements on pressure-driven phase transitions in Mott insulators as well as the new iron pnictide superconductors, we show that first principles Car-Parrinello molecular dynamics calculations are a powerful method to describe the microscopic origin of such transitions. We present results for (i) the pressure-induced insulator to metal phase transition in the prototypical Mott insulator TiOCl as well as (ii) the pressure-induced structural and magnetic phase transitions in the family of correlated metals AFe(2)As(2) (A = Ca, Sr, Ba). Comparison of our predictions with existing experimental results yields very good agreement.
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Affiliation(s)
- Yu-Zhong Zhang
- Institut für Theoretische Physik, Goethe-Universität Frankfurt, Max-von-Laue-Strasse 1, 60438 Frankfurt am Main, Germany
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Chernyshova IV, Ponnurangam S, Somasundaran P. On the origin of an unusual dependence of (bio)chemical reactivity of ferric hydroxides on nanoparticle size. Phys Chem Chem Phys 2010; 12:14045-56. [DOI: 10.1039/c0cp00168f] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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46
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Ming X, Meng X, Hu F, Wang CZ, Huang ZF, Fan HG, Chen G. Pressure-induced magnetic moment collapse and insulator-to-semimetal transition in BiCoO(3). JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2009; 21:295902. [PMID: 21828538 DOI: 10.1088/0953-8984/21/29/295902] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The structural stability, magnetic properties and electronic structure of tetragonal BiCoO(3) under pressure have been studied by first-principles density functional calculations. The calculated results reveal that no tetragonal-to-cubic and ferroelectric-to-paraelectric phase transitions occur up to 30 GPa with a volume compression of about 25%. An electronic spin crossover transition of the Co(3+) ion from the high-spin to nonmagnetic low-spin configuration (magnetic moment collapse) occurs at 4 GPa by about 4.87% volume compression, which is concomitant with a first-order isosymmetric transition and an insulator-to-semimetal transition. The metallization in BiCoO(3) is driven by the spin-state transition at high pressure. Coexistence of the structural, spin-state and insulator-to-semimetal transitions implies that there is a strong coupling among the lattice, spin and charge degrees of freedom in BiCoO(3).
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Affiliation(s)
- Xing Ming
- Department of Materials Science, College of Materials Science and Engineering, Jilin University, Changchun 130012, People's Republic of China
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Kunes J, Korotin DM, Korotin MA, Anisimov VI, Werner P. Pressure-driven metal-insulator transition in hematite from dynamical mean-field theory. PHYSICAL REVIEW LETTERS 2009; 102:146402. [PMID: 19392460 DOI: 10.1103/physrevlett.102.146402] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2008] [Indexed: 05/27/2023]
Abstract
The local density approximation combined with dynamical mean-field theory is applied to study the paramagnetic and magnetically ordered phases of hematite Fe2O3 as a function of volume. As the volume is decreased, a simultaneous first-order insulator-metal and high-spin to low-spin transition occurs close to the experimental value of the critical volume. The high-spin insulating phase is destroyed by a progressive reduction of the spectral gap with increasing pressure, upon closing of which the high-spin phase becomes unstable. We conclude that the transition in Fe2O3 at approximately 50 GPa can be described as an electronically driven volume collapse.
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Affiliation(s)
- J Kunes
- Theoretical Physics III, Center for Electronic Correlations and Magnetism, Institute of Physics, University of Augsburg, Augsburg 86135, Germany
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48
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Kostadinov IZ, Patton BR. Second critical point in first order metal-insulator transitions. PHYSICAL REVIEW LETTERS 2008; 101:226407. [PMID: 19113498 DOI: 10.1103/physrevlett.101.226407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2008] [Indexed: 05/27/2023]
Abstract
For first order metal-insulator transitions we show that, together with the dc conductance zero, there is a second critical point where the dielectric constant becomes zero and further turns negative. At this point the metallic reflectivity sharply increases. The two points can be separated by a phase separation state in a 3D disordered system but may tend to merge in 2D. For illustration we evaluate the dielectric function in a simple effective medium approximation and show that at the second point it turns negative. We reproduce the experimental data on a typical Mott insulator such as MnO, demonstrating the presence of the two points clearly. We discuss other experiments for studies of the phase separation state and a similar phase separation in superconductors with insulating inclusions.
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Affiliation(s)
- Ivan Z Kostadinov
- Department of Physics, The Ohio State University, Columbus, Ohio 43210, USA.
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49
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Zhang YZ, Jeschke HO, Valentí R. Two pressure-induced transitions in TiOCl: Mott insulator to anisotropic metal. PHYSICAL REVIEW LETTERS 2008; 101:136406. [PMID: 18851472 DOI: 10.1103/physrevlett.101.136406] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2008] [Indexed: 05/26/2023]
Abstract
Using Car-Parrinello molecular dynamics we investigate the behavior of the low-dimensional multiorbital Mott insulator TiOCl under pressure. We show that the system undergoes two consecutive phase transitions, first at Pc from a Mott-insulator to a metallic phase in the ab plane with a strong Ti-Ti dimerization along b. At a pressure Pc' > Pc the dimerization disappears and the system behaves as a uniform metal. This second transition has not yet been reported experimentally. We show that the insulator-to-metal transition at Pc is driven by the widening of the bandwidth rather than structural changes or reduction of crystal field splittings and it shows a redistribution of the electronic occupation within the t2g bands. Our computed pressure-dependent lattice parameters are consistent with experimental observations and the existing controversy on the change of crystal symmetry at high pressures is discussed.
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Affiliation(s)
- Yu-Zhong Zhang
- Institut für Theoretische Physik, Goethe-Universität Frankfurt, Max-von-Laue-Strasse 1, 60438 Frankfurt am Main, Germany
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50
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Leonov I, Binggeli N, Korotin D, Anisimov VI, Stojić N, Vollhardt D. Structural relaxation due to electronic correlations in the paramagnetic insulator KCuF3. PHYSICAL REVIEW LETTERS 2008; 101:096405. [PMID: 18851632 DOI: 10.1103/physrevlett.101.096405] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2008] [Indexed: 05/26/2023]
Abstract
A computational scheme for the investigation of complex materials with strongly interacting electrons is formulated which is able to treat atomic displacements, and hence structural relaxation, caused by electronic correlations. It combines ab initio band structure and dynamical mean-field theory and is implemented in terms of plane-wave pseudopotentials. The equilibrium Jahn-Teller distortion and antiferro-orbital order found for paramagnetic KCuF3 agree well with experiment.
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Affiliation(s)
- I Leonov
- Abdus Salam International Center for Theoretical Physics, Trieste 34014, Italy
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