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Hunter A, Beck S, Cappelli E, Margot F, Straub M, Alexanian Y, Gatti G, Watson MD, Kim TK, Cacho C, Plumb NC, Shi M, Radović M, Sokolov DA, Mackenzie AP, Zingl M, Mravlje J, Georges A, Baumberger F, Tamai A. Fate of Quasiparticles at High Temperature in the Correlated Metal Sr_{2}RuO_{4}. PHYSICAL REVIEW LETTERS 2023; 131:236502. [PMID: 38134803 DOI: 10.1103/physrevlett.131.236502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Accepted: 11/08/2023] [Indexed: 12/24/2023]
Abstract
We study the temperature evolution of quasiparticles in the correlated metal Sr_{2}RuO_{4}. Our angle resolved photoemission data show that quasiparticles persist up to temperatures above 200 K, far beyond the Fermi liquid regime. Extracting the quasiparticle self-energy, we demonstrate that the quasiparticle residue Z increases with increasing temperature. Quasiparticles eventually disappear on approaching the bad metal state of Sr_{2}RuO_{4} not by losing weight but via excessive broadening from super-Planckian scattering. We further show that the Fermi surface of Sr_{2}RuO_{4}-defined as the loci where the spectral function peaks-deflates with increasing temperature. These findings are in semiquantitative agreement with dynamical mean field theory calculations.
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Affiliation(s)
- A Hunter
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland
| | - S Beck
- Center for Computational Quantum Physics, Flatiron Institute, 162 Fifth Avenue, New York, New York 10010, USA
| | - E Cappelli
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland
| | - F Margot
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland
| | - M Straub
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland
| | - Y Alexanian
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland
| | - G Gatti
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland
| | - M D Watson
- Diamond Light Source, Harwell Campus, Didcot, OX11 0DE, United Kingdom
| | - T K Kim
- Diamond Light Source, Harwell Campus, Didcot, OX11 0DE, United Kingdom
| | - C Cacho
- Diamond Light Source, Harwell Campus, Didcot, OX11 0DE, United Kingdom
| | - N C Plumb
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - M Shi
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - M Radović
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - D A Sokolov
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
| | - A P Mackenzie
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
- Scottish Universities Physics Alliance, School of Physics and Astronomy, University of St. Andrews, St. Andrews KY16 9SS, United Kingdom
| | - M Zingl
- Center for Computational Quantum Physics, Flatiron Institute, 162 Fifth Avenue, New York, New York 10010, USA
| | - J Mravlje
- Department of Theoretical Physics, Institute Jozef Stefan, Jamova 39, SI-1001 Ljubljana, Slovenia
- Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, SI-1000 Ljubljana
| | - A Georges
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland
- Center for Computational Quantum Physics, Flatiron Institute, 162 Fifth Avenue, New York, New York 10010, USA
- Collège de France, 11 Place Marcelin Berthelot, 75005 Paris, France
- Centre de Physique Théorique, Ecole Polytechnique, CNRS, Institut Polytechnique de Paris, 91128 Palaiseau Cedex, France
| | - F Baumberger
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - A Tamai
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland
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2
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Li Z, Zhang Z, Zhou X. Chemical Modulation of Metal-Insulator Transition toward Multifunctional Applications in Vanadium Dioxide Nanostructures. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023; 19:e2305234. [PMID: 37394705 DOI: 10.1002/smll.202305234] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Indexed: 07/04/2023]
Abstract
The metal-insulator transition (MIT) of vanadium dioxide (VO2 ) has been of great interest in materials science for both fundamental understanding of strongly correlated physics and a wide range of applications in optics, thermotics, spintronics, and electronics. Due to the merits of chemical interaction with accessibility, versatility, and tunability, chemical modification provides a new perspective to regulate the MIT of VO2 , endowing VO2 with exciting properties and improved functionalities. In the past few years, plenty of efforts have been devoted to exploring innovative chemical approaches for the synthesis and MIT modulation of VO2 nanostructures, greatly contributing to the understanding of electronic correlations and development of MIT-driven functionalities. Here, this comprehensive review summarizes the recent achievements in chemical synthesis of VO2 and its MIT modulation involving hydrogen incorporation, composition engineering, surface modification, and electrochemical gating. The newly appearing phenomena, mechanism of electronic correlation, and structural instability are discussed. Furthermore, progresses related to MIT-driven applications are presented, such as the smart window, optoelectronic detector, thermal microactuator, thermal radiation coating, spintronic device, memristive, and neuromorphic device. Finally, the challenges and prospects in future research of chemical modulation and functional applications of VO2 MIT are also provided.
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Affiliation(s)
- Zejun Li
- School of Physics, Frontiers Science Center for Mobile Information Communication and Security, Southeast University, Nanjing, 211189, China
- Purple Mountain Laboratories, Nanjing, 211111, China
| | - Zhi Zhang
- School of Physics, Frontiers Science Center for Mobile Information Communication and Security, Southeast University, Nanjing, 211189, China
| | - Xiaoli Zhou
- School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing, 210094, China
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3
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Brar J, Singh S, Kuga K, Sharma P, M B, Takeuchi T, Bindu R. Lattice effects on the physical properties of half-doped perovskite ruthenates. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2023; 35:195402. [PMID: 36867880 DOI: 10.1088/1361-648x/acc15d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2022] [Accepted: 03/03/2023] [Indexed: 06/18/2023]
Abstract
We investigate the unusual phase transitions in SrRuO3and Sr0.5Ca0.5Ru1-xCrxO3(x = 0, 0.05 and 0.1) employing x-ray diffraction, resistivity, magnetic studies and x-ray photoemission spectroscopy. Our results show the compounds undergo a crossover from itinerant ferromagnetism to localized ferromagnetism. The combined studies suggest Ru and Cr be in the 4+ valence state. A Griffith phase and an enhancement in Curie temperature (Tc) from 38 K to 107 K are observed with Cr doping. A shift in the chemical potential towards the valence band is observed with Cr doping. In the metallic samples, interestingly, a direct link between the resistivity and orthorhombic strain is observed. We also observe a connection between orthorhombic strain andTcin all the samples. Detailed studies in this direction will be helpful to choose suitable substrate materials for thin-film/device fabrication and hence manoeuvre its properties. In the non-metallic samples, the resistivity is mainly governed due to disorder, electron-electron correlation effects and a reduction in the number of electrons at the Fermi level. The value of the resistivity for the 5% Cr doped sample suggests semi-metallic behaviour. Understanding its nature in detail using electron spectroscopic techniques could unravel the possibility of its utility in high-mobility transistors at room temperature and its combined property with ferromagnetism will be helpful in making spintronic devices.
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Affiliation(s)
- Jaskirat Brar
- School of Physical Sciences, Indian Institute of Technology Mandi, Kamand, Himachal Pradesh 175005, India
| | - Saurabh Singh
- Toyota Technological Institute, Nagoya, Aichi 468-8511, Japan
- Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012, Japan
| | - Kentaro Kuga
- Toyota Technological Institute, Nagoya, Aichi 468-8511, Japan
- Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012, Japan
| | - Priyamedha Sharma
- School of Physical Sciences, Indian Institute of Technology Mandi, Kamand, Himachal Pradesh 175005, India
| | - Bharath M
- School of Physical Sciences, Indian Institute of Technology Mandi, Kamand, Himachal Pradesh 175005, India
| | - Tsunehiro Takeuchi
- Toyota Technological Institute, Nagoya, Aichi 468-8511, Japan
- Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012, Japan
| | - R Bindu
- School of Physical Sciences, Indian Institute of Technology Mandi, Kamand, Himachal Pradesh 175005, India
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4
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Hohl T, Kremer RK, Ebbinghaus SG, Khan SA, Minár J, Hoch C. Influence of Disorder on the Bad Metal Behavior in Polar Amalgams. Inorg Chem 2023; 62:3965-3975. [PMID: 36821862 DOI: 10.1021/acs.inorgchem.2c04430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Abstract
The two new ternary amalgams K1-xRbxHg11 [x = 0.472(7)] and Cs3-xCaxHg20 [x = 0.20(3)] represent two different examples of how to create ternary compounds from binaries by statistical atom substitution. K1-xRbxHg11 is a Vegard-type mixed crystal of the isostructural binaries KHg11 and RbHg11 [cubic, BaHg11 structure type, space group Pm3̅m, a = 9.69143(3) Å, Rietveld refinement], whereas Cs3-xCaxHg20 is a substitution variant of the Rb3Hg20 structure type [cubic, space group Pm3̅n, a = 10.89553(14) Å, Rietveld refinement] for which a fully substituted isostructural binary Ca phase is unknown. In K1-xRbxHg11, the valence electron concentration (VEC) is not changed by the substitution, whereas in Cs3-xCaxHg20, the VEC increases with the Ca content. Amalgams of electropositive metals form polar metal bonds and show "bad metal" properties. By thermal analysis, magnetic susceptibility and resistivity measurements, and density functional theory calculations of the electronic structures, we investigate the effect of the structural disorder introduced by creating mixed-atom occupation on the physical properties of the two new polar amalgam systems.
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Affiliation(s)
- Timotheus Hohl
- Department Chemie, Ludwig-Maximilians-Universität München, 81377 München, Germany
| | - Reinhard K Kremer
- Max-Planck-Institut für Festkörperforschung Stuttgart, 70569 Stuttgart, Germany
| | - Stefan G Ebbinghaus
- Institut für Chemie, Martin-Luther-Universität Halle-Wittenberg, 06108 Halle (Saale), Germany
| | - Saleem A Khan
- New Technologies Research Center, University of West Bohemia, 30100 Pilsen, Czech Republic
| | - Ján Minár
- New Technologies Research Center, University of West Bohemia, 30100 Pilsen, Czech Republic
| | - Constantin Hoch
- Department Chemie, Ludwig-Maximilians-Universität München, 81377 München, Germany
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5
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Murthy C, Pandey A, Esterlis I, Kivelson SA. A stability bound on the [Formula: see text]-linear resistivity of conventional metals. Proc Natl Acad Sci U S A 2023; 120:e2216241120. [PMID: 36634139 PMCID: PMC9934301 DOI: 10.1073/pnas.2216241120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 12/06/2022] [Indexed: 01/13/2023] Open
Abstract
Perturbative considerations account for the properties of conventional metals, including the range of temperatures where the transport scattering rate is 1/τtr = 2πλT, where λ is a dimensionless strength of the electron-phonon coupling. The fact that measured values satisfy λ ≲ 1 has been noted in the context of a possible "Planckian" bound on transport. However, since the electron-phonon scattering is quasielastic in this regime, no such Planckian considerations can be relevant. We present and analyze Monte Carlo results on the Holstein model which show that a different sort of bound is at play: a "stability" bound on λ consistent with metallic transport. We conjecture that a qualitatively similar bound on the strength of residual interactions, which is often stronger than Planckian, may apply to metals more generally.
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Affiliation(s)
| | - Akshat Pandey
- Department of Physics, Stanford University, Stanford, CA93405
| | - Ilya Esterlis
- Department of Physics, Harvard University, Cambridge, MA02138
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6
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Wang A, Wu L, Du Q, Naamneh M, Brito WH, Abeykoon AM, Pudelko WR, Jandke J, Liu Y, Plumb NC, Kotliar G, Dobrosavljevic V, Radovic M, Zhu Y, Petrovic C. Mooij Law Violation from Nanoscale Disorder. NANO LETTERS 2022; 22:6900-6906. [PMID: 35976289 DOI: 10.1021/acs.nanolett.2c01282] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Nanoscale inhomogeneity can profoundly impact properties of two-dimensional van der Waals materials. Here, we reveal how sulfur substitution on the selenium atomic sites in Fe1-ySe1-xSx (0 ≤ x ≤ 1, y ≤ 0.1) causes Fe-Ch (Ch = Se, S) bond length differences and strong disorder for 0.4 ≤ x ≤ 0.8. There, the superconducting transition temperature Tc is suppressed and disorder-related scattering is enhanced. The high-temperature metallic resistivity in the presence of strong disorder exceeds the Mott limit and provides an example of the violation of Matthiessen's rule and the Mooij law, a dominant effect when adding moderate disorder past the Drude/Matthiessen's regime in all materials. The scattering mechanism responsible for the resistivity above the Mott limit is unrelated to phonons and arises for strong Se/S atom disorder in the tetrahedral surrounding of Fe. Our findings shed light on the intricate connection between the nanostructural details and the unconventional scattering mechanism, which is possibly related to charge-nematic or magnetic spin fluctuations.
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Affiliation(s)
- Aifeng Wang
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Lijun Wu
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Qianheng Du
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, United States
- Department of Materials Science and Chemical Engineering, Stony Brook University, Stony Brook, New York 11790, United States
| | - Muntaser Naamneh
- Department of Physics, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
| | - Walber Hugo Brito
- Departamento de Física, Universidade Federal de Minas Gerais, C. P. 702, 30123-970 Belo Horizonte, Minas Gerais, Brazil
| | - Am Milinda Abeykoon
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Wojciech Radoslaw Pudelko
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen, Switzerland
- Physik-Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - Jasmin Jandke
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen, Switzerland
| | - Yu Liu
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Nicholas C Plumb
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen, Switzerland
| | - Gabriel Kotliar
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, United States
- Department of Physics and Astronomy, Center for Materials Theory, Rutgers University, Piscataway, New Jersey 08854, United States
| | - Vladimir Dobrosavljevic
- Department of Physics and National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32306, United States
| | - Milan Radovic
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen, Switzerland
| | - Yimei Zhu
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Cedomir Petrovic
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, United States
- Department of Materials Science and Chemical Engineering, Stony Brook University, Stony Brook, New York 11790, United States
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7
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Abstract
In traditional metals, the temperature (
T
) dependence of electrical resistivity vanishes at low or high
T
, albeit for different reasons. Here, we review a class of materials, known as “strange” metals, that can violate both of these principles. In strange metals, the change in slope of the resistivity as the mean free path drops below the lattice constant, or as
T
→ 0, can be imperceptible, suggesting continuity between the charge carriers at low and high
T
. We focus on transport and spectroscopic data on candidate strange metals in an effort to isolate and identify a unifying physical principle. Special attention is paid to quantum criticality, Planckian dissipation, Mottness, and whether a new gauge principle is needed to account for the nonlocal transport seen in these materials.
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Affiliation(s)
- Philip W. Phillips
- Department of Physics and Institute for Condensed Matter Theory, University of Illinois, Urbana, IL 61801, USA
| | - Nigel E. Hussey
- H. H. Wills Physics Laboratory, University of Bristol, Bristol BS8 1TL, UK
- High Field Magnet Laboratory (HFML-EMFL) and Institute for Molecules and Materials, Radboud University, 6525 ED Nijmegen, Netherlands
| | - Peter Abbamonte
- Department of Physics, University of Illinois, Urbana, IL 61801, USA
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8
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How to Recognize the Universal Aspects of Mott Criticality? CRYSTALS 2022. [DOI: 10.3390/cryst12070932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In this paper we critically discuss several examples of two-dimensional electronic systems displaying interaction-driven metal-insulator transitions of the Mott (or Wigner–Mott) type, including dilute two-dimension electron gases (2DEG) in semiconductors, Mott organic materials, as well as the recently discovered transition-metal dichalcogenide (TMD) moiré bilayers. Remarkably similar behavior is found in all these systems, which is starting to paint a robust picture of Mott criticality. Most notable, on the metallic side a resistivity maximum is observed whose temperature scale vanishes at the transition. We compare the available experimental data on these systems to three existing theoretical scenarios: spinon theory, Dynamical Mean Field Theory (DMFT) and percolation theory. We show that the DMFT and percolation pictures for Mott criticality can be distinguished by studying the origins of the resistivity maxima using an analysis of the dielectric response.
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9
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Scaling of the strange-metal scattering in unconventional superconductors. Nature 2022; 602:431-436. [PMID: 35173341 DOI: 10.1038/s41586-021-04305-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 11/29/2021] [Indexed: 11/08/2022]
Abstract
Marked evolution of properties with minute changes in the doping level is a hallmark of the complex chemistry that governs copper oxide superconductivity as manifested in the celebrated superconducting domes and quantum criticality taking place at precise compositions1-4. The strange-metal state, in which the resistivity varies linearly with temperature, has emerged as a central feature in the normal state of copper oxide superconductors5-9. The ubiquity of this behaviour signals an intimate link between the scattering mechanism and superconductivity10-12. However, a clear quantitative picture of the correlation has been lacking. Here we report the observation of precise quantitative scaling laws among the superconducting transition temperature (Tc), the linear-in-T scattering coefficient (A1) and the doping level (x) in electron-doped copper oxide La2-xCexCuO4 (LCCO). High-resolution characterization of epitaxial composition-spread films, which encompass the entire overdoped range of LCCO, has enabled us to systematically map its structural and transport properties with unprecedented accuracy and with increments of Δx = 0.0015. We have uncovered the relations Tc ~ (xc - x)0.5 ~ (A1□)0.5, where xc is the critical doping in which superconductivity disappears and A1□ is the coefficient of the linear resistivity per CuO2 plane. The striking similarity of the Tc versus A1□ relation among copper oxides, iron-based and organic superconductors may be an indication of a common mechanism of the strange-metal behaviour and unconventional superconductivity in these systems.
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10
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Are Heavy Fermion Strange Metals Planckian? CRYSTALS 2022; 12:251. [PMID: 35910592 PMCID: PMC8979306 DOI: 10.3390/cryst12020251] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Accepted: 02/10/2022] [Indexed: 11/22/2022]
Abstract
Strange metal behavior refers to a linear temperature dependence of the electrical resistivity that is not due to electron–phonon scattering. It is seen in numerous strongly correlated electron systems, from the heavy fermion compounds, via transition metal oxides and iron pnictides, to magic angle twisted bi-layer graphene, frequently in connection with unconventional or “high temperature” superconductivity. To achieve a unified understanding of these phenomena across the different materials classes is a central open problem in condensed matter physics. Tests whether the linear-in-temperature law might be dictated by Planckian dissipation—scattering with the rate ∼kBT/ℏ—are receiving considerable attention. Here we assess the situation for strange metal heavy fermion compounds. They allow to probe the regime of extreme correlation strength, with effective mass or Fermi velocity renormalizations in excess of three orders of magnitude. Adopting the same procedure as done in previous studies, i.e., assuming a simple Drude conductivity with the above scattering rate, we find that for these strongly renormalized quasiparticles, scattering is much weaker than Planckian, implying that the linear temperature dependence should be due to other effects. We discuss implications of this finding and point to directions for further work.
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11
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Raychaudhuri P, Dutta S. Phase fluctuations in conventional superconductors. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 34:083001. [PMID: 34731851 DOI: 10.1088/1361-648x/ac360b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Accepted: 11/03/2021] [Indexed: 06/13/2023]
Abstract
Within the Bardeen-Cooper-Schrieffer (BCS) theory, superconductivity is entirely governed by the pairing energy scale, which gives rise to the superconducting energy gap, Δ. However, another important energy scale, the superfluid phase stiffness,J, which determines the resilience of the superconductor to phase-fluctuations is normally ignored. The spectacular success of BCS theory owes to the fact that in conventional superconductorsJis normally several orders of magnitude larger than Δ and thus an irrelevant energy scale. However, in certain situations such as in the presence of low carrier density, strong disorder, at low-dimensions or in granular superconductors,Jcan drastically come down and even become smaller than Δ. In such situations, the temperature and magnetic field evolution of superconducting properties is governed by phase fluctuations, which gives rise to novel electronic states where signatures of electronic pairing continue to exist even when the zero resistance state is destroyed. In this article, we will review the recent experimental developments on the study of phase fluctuations in conventional superconductors.
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Affiliation(s)
- Pratap Raychaudhuri
- Department of Condensed Matter Physics and Materials Science, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005, India
| | - Surajit Dutta
- Department of Condensed Matter Physics and Materials Science, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005, India
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12
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Continuous Mott transition in semiconductor moiré superlattices. Nature 2021; 597:350-354. [PMID: 34526709 DOI: 10.1038/s41586-021-03853-0] [Citation(s) in RCA: 67] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 07/22/2021] [Indexed: 11/08/2022]
Abstract
The evolution of a Landau Fermi liquid into a non-magnetic Mott insulator with increasing electronic interactions is one of the most puzzling quantum phase transitions in physics1-6. The vicinity of the transition is believed to host exotic states of matter such as quantum spin liquids4-7, exciton condensates8 and unconventional superconductivity1. Semiconductor moiré materials realize a highly controllable Hubbard model simulator on a triangular lattice9-22, providing a unique opportunity to drive a metal-insulator transition (MIT) via continuous tuning of the electronic interactions. Here, by electrically tuning the effective interaction strength in MoTe2/WSe2 moiré superlattices, we observe a continuous MIT at a fixed filling of one electron per unit cell. The existence of quantum criticality is supported by the scaling collapse of the resistance, a continuously vanishing charge gap as the critical point is approached from the insulating side, and a diverging quasiparticle effective mass from the metallic side. We also observe a smooth evolution of the magnetic susceptibility across the MIT and no evidence of long-range magnetic order down to ~5% of the Curie-Weiss temperature. This signals an abundance of low-energy spinful excitations on the insulating side that is further corroborated by the Pomeranchuk effect observed on the metallic side. Our results are consistent with the universal critical theory of a continuous Mott transition in two dimensions4,23.
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13
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Incoherent transport across the strange-metal regime of overdoped cuprates. Nature 2021; 595:661-666. [PMID: 34321672 DOI: 10.1038/s41586-021-03622-z] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 05/04/2021] [Indexed: 02/07/2023]
Abstract
Strange metals possess highly unconventional electrical properties, such as a linear-in-temperature resistivity1-6, an inverse Hall angle that varies as temperature squared7-9 and a linear-in-field magnetoresistance10-13. Identifying the origin of these collective anomalies has proved fundamentally challenging, even in materials such as the hole-doped cuprates that possess a simple bandstructure. The prevailing consensus is that strange metallicity in the cuprates is tied to a quantum critical point at a doping p* inside the superconducting dome14,15. Here we study the high-field in-plane magnetoresistance of two superconducting cuprate families at doping levels beyond p*. At all dopings, the magnetoresistance exhibits quadrature scaling and becomes linear at high values of the ratio of the field and the temperature, indicating that the strange-metal regime extends well beyond p*. Moreover, the magnitude of the magnetoresistance is found to be much larger than predicted by conventional theory and is insensitive to both impurity scattering and magnetic field orientation. These observations, coupled with analysis of the zero-field and Hall resistivities, suggest that despite having a single band, the cuprate strange-metal region hosts two charge sectors, one containing coherent quasiparticles, the other scale-invariant 'Planckian' dissipators.
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14
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Groshev AG, Arzhnikov AK. Thermal fluctuations in superconducting phases with chiral d+ i dand ssymmetry on a triangular lattice. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:215604. [PMID: 33592591 DOI: 10.1088/1361-648x/abe6e0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Accepted: 02/16/2021] [Indexed: 06/12/2023]
Abstract
The behavior of thermal fluctuations of a superconducting order parameter with extendedsand chirald+ idsymmetry is investigated. The study is carried out on a triangular lattice within the framework of the quasi-two-dimensional single-band model with attraction between electrons at neighboring sites. The method of consistent consideration of the order parameter fluctuations and the charge carrier scattering by fluctuations of coupled electron pairs, based on the theory of functional integration is used. The distribution functions of the phase fluctuation probabilities depending on temperature and charge carrier concentration are obtained. The temperature dependences of the amplitudes of the averaged superconducting order parameter are calculated. A phase diagram of superconducting states is constructed for the entire range of variation in the charge carrier concentration 0 <n< 2. Near the boundaries of this range, topologically trivial superconducting states with extendedssymmetry are realized, while a superconducting state with topologically nontrivial chirald+ idsymmetry is realized between them. The calculated anomalous self-energies are compared with the experimental ones obtained using machine learning techniques.
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Affiliation(s)
- A G Groshev
- Udmurt Federal Research Center of the Ural Branch of the Russian Academy of Sciences, T. Baramzinoy st. 34, Izhevsk 426067, Russia
| | - A K Arzhnikov
- Udmurt Federal Research Center of the Ural Branch of the Russian Academy of Sciences, T. Baramzinoy st. 34, Izhevsk 426067, Russia
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15
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Wang ZC, Rogers JD, Yao X, Nichols R, Atay K, Xu B, Franklin J, Sochnikov I, Ryan PJ, Haskel D, Tafti F. Colossal Magnetoresistance without Mixed Valence in a Layered Phosphide Crystal. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2005755. [PMID: 33511677 DOI: 10.1002/adma.202005755] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 01/07/2021] [Indexed: 06/12/2023]
Abstract
Materials with strong magnetoresistive responses are the backbone of spintronic technology, magnetic sensors, and hard drives. Among them, manganese oxides with a mixed valence and a cubic perovskite structure stand out due to their colossal magnetoresistance (CMR). A double exchange interaction underlies the CMR in manganates, whereby charge transport is enhanced when the spins on neighboring Mn3+ and Mn4+ ions are parallel. Prior efforts to find different materials or mechanisms for CMR resulted in a much smaller effect. Here an enormous CMR at low temperatures in EuCd2 P2 without manganese, oxygen, mixed valence, or cubic perovskite structure is shown. EuCd2 P2 has a layered trigonal lattice and exhibits antiferromagnetic ordering at 11 K. The magnitude of CMR (104 %) in as-grown crystals of EuCd2 P2 rivals the magnitude in optimized thin films of manganates. The magnetization, transport, and synchrotron X-ray data suggest that strong magnetic fluctuations are responsible for this phenomenon. The realization of CMR at low temperatures without heterovalency leads to a new regime for materials and technologies related to antiferromagnetic spintronics.
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Affiliation(s)
- Zhi-Cheng Wang
- Departments of Physics, Boston College, 140 Commonwealth Avenue, Chestnut Hill, MA, 02467, USA
| | - Jared D Rogers
- Departments of Physics, Boston College, 140 Commonwealth Avenue, Chestnut Hill, MA, 02467, USA
| | - Xiaohan Yao
- Departments of Physics, Boston College, 140 Commonwealth Avenue, Chestnut Hill, MA, 02467, USA
| | - Renee Nichols
- Departments of Physics, Boston College, 140 Commonwealth Avenue, Chestnut Hill, MA, 02467, USA
| | - Kemal Atay
- Departments of Physics, Boston College, 140 Commonwealth Avenue, Chestnut Hill, MA, 02467, USA
| | - Bochao Xu
- Physics Department, University of Connecticut, Storrs, CT, 06269, USA
| | - Jacob Franklin
- Physics Department, University of Connecticut, Storrs, CT, 06269, USA
| | - Ilya Sochnikov
- Physics Department, University of Connecticut, Storrs, CT, 06269, USA
- Institute of Material Science, University of Connecticut, Storrs, CT, 06269, USA
| | - Philip J Ryan
- Advanced Photon Source, Argonne National Laboratory, Argonne, IL, 60439, USA
- School of Physical Sciences, Dublin City University, Dublin 9, D09 V209, Ireland
| | - Daniel Haskel
- Advanced Photon Source, Argonne National Laboratory, Argonne, IL, 60439, USA
| | - Fazel Tafti
- Departments of Physics, Boston College, 140 Commonwealth Avenue, Chestnut Hill, MA, 02467, USA
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16
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Cha P, Wentzell N, Parcollet O, Georges A, Kim EA. Linear resistivity and Sachdev-Ye-Kitaev (SYK) spin liquid behavior in a quantum critical metal with spin-1/2 fermions. Proc Natl Acad Sci U S A 2020; 117:18341-18346. [PMID: 32699148 PMCID: PMC7414094 DOI: 10.1073/pnas.2003179117] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
"Strange metals" with resistivity depending linearly on temperature T down to low T have been a long-standing puzzle in condensed matter physics. Here, we consider a lattice model of itinerant spin-[Formula: see text] fermions interacting via onsite Hubbard interaction and random infinite-ranged spin-spin interaction. We show that the quantum critical point associated with the melting of the spin-glass phase by charge fluctuations displays non-Fermi liquid behavior, with local spin dynamics identical to that of the Sachdev-Ye-Kitaev family of models. This extends the quantum spin liquid dynamics previously established in the large-M limit of [Formula: see text] symmetric models to models with physical [Formula: see text] spin-[Formula: see text] electrons. Remarkably, the quantum critical regime also features a Planckian linear-T resistivity associated with a T-linear scattering rate and a frequency dependence of the electronic self-energy consistent with the marginal Fermi liquid phenomenology.
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Affiliation(s)
- Peter Cha
- Department of Physics, Cornell University, Ithaca, NY 14853;
| | - Nils Wentzell
- Center for Computational Quantum Physics, The Flatiron Institute, New York, NY, 10010
| | - Olivier Parcollet
- Center for Computational Quantum Physics, The Flatiron Institute, New York, NY, 10010
- Université Paris-Saclay, CNRS, CEA, Institut de physique théorique, 91191, Gif-sur-Yvette, France
| | - Antoine Georges
- Center for Computational Quantum Physics, The Flatiron Institute, New York, NY, 10010
- Collège de France, 75005 Paris, France
- Centre de Physique Théorique, Ecole Polytechnique, CNRS, 91128 Palaiseau Cedex, France
- Department of Quantum Matter Physics, University of Geneva, 1211 Geneva 4, Switzerland
| | - Eun-Ah Kim
- Department of Physics, Cornell University, Ithaca, NY 14853
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17
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Gupta R, Rawat R, Pramanik AK. Electronic properties in itinerant ferromagnet SrRu 1-x Ti x O 3. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:285502. [PMID: 32160606 DOI: 10.1088/1361-648x/ab7f08] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Here, we study the electrical transport and specific heat in 4d based ferromagnetic material SrRuO3 and its Ti substituted SrRu1-x Ti x O3 series (x ⩽ 0.7). The SrRuO3 is a metal and shows itinerant ferromagnetism with transition temperature T c ∼ 160 K. The nonmagnetic Ti4+ (3d 0) substitution would not only weaken the active Ru-O-Ru channel but is also expected to tune the electronic density and electron correlation effect. A metal to insulator transition has been observed around x ∼ 0.4. The nature of charge transport in paramagnetic-metallic state (x ⩽ 0.4) and in insulating state (x > 0.4) follows modified Mott's variable range hopping model. In ferromagnetic-metallic state, resistivity shows a T 2 dependence below T c which though modifies to T 3/2 dependence at low temperature. In Ti substituted samples, temperature range for T 3/2 dependence extends to higher temperature. Interestingly, this T 3/2 dependence dominates in whole ferromagnetic regime in presence of magnetic field. This evolution of electronic transport behavior can be explained within the framework of Fermi liquid theory and electron-magnon scattering mechanism. The negative magnetoresistance exhibits a hysteresis and a crossover between negative and positive value with magnetic field which is connected with magnetic behavior in series. The decreasing electronic coefficient of specific heat with x supports the increasing insulating behavior in present series. We calculate a high Kadowaki-Woods ratio (x ⩽ 0.3) for SrRuO3 which increases with substitution concentration. This signifies an increasing electronic correlation effect with substitution concentration.
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Affiliation(s)
- Renu Gupta
- School of Physical Sciences, Jawaharlal Nehru University, New Delhi-110067, India
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18
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Armbrüster M. Intermetallic compounds in catalysis - a versatile class of materials meets interesting challenges. SCIENCE AND TECHNOLOGY OF ADVANCED MATERIALS 2020; 21:303-322. [PMID: 33628119 PMCID: PMC7889166 DOI: 10.1080/14686996.2020.1758544] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 04/15/2020] [Accepted: 04/17/2020] [Indexed: 06/12/2023]
Abstract
The large and vivid field of intermetallic compounds in catalysis is reviewed to identify necessities, strategies and new developments making use of the advantageous catalytic properties of intermetallic compounds. Since recent reviews summarizing contributions in heterogeneous catalysis as well as electrocatalysis are available, this contribution is not aiming at a comprehensive literature review. To introduce the field, first the interesting nature of intermetallic compounds is elaborated - including possibilities as well as requirements to address catalytic questions. Subsequently, this review focuses on exciting developments and example success stories of intermetallic compounds in catalysis. Since many of these are based on recent advances in synthesis, a short overview of synthesis and characterisation is included. Thus, this contribution aims to be an introduction to the newcomer as well as being helpful to the experienced researcher by summarising the different approaches. Selected examples from literature are chosen to illustrate the versatility of intermetallic compounds in heterogeneous catalysis where the emphasis is on developments since the last comprehensive review in the field.
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Affiliation(s)
- Marc Armbrüster
- Faculty of Natural Sciences, Institute of Chemistry, Materials for Innovative Energy Concepts, Chemnitz University of Technology, Chemnitz, Germany
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19
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Tunable resistivity exponents in the metallic phase of epitaxial nickelates. Nat Commun 2020; 11:2949. [PMID: 32527995 PMCID: PMC7289814 DOI: 10.1038/s41467-020-16740-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Accepted: 05/15/2020] [Indexed: 11/12/2022] Open
Abstract
We report a detailed analysis of the electrical resistivity exponent of thin films of NdNiO3 as a function of epitaxial strain. Thin films under low strain conditions show a linear dependence of the resistivity versus temperature, consistent with a classical Fermi gas ruled by electron-phonon interactions. In addition, the apparent temperature exponent, n, can be tuned with the epitaxial strain between n = 1 and n = 3. We discuss the critical role played by quenched random disorder in the value of n. Our work shows that the assignment of Fermi/Non-Fermi liquid behaviour based on experimentally obtained resistivity exponents requires an in-depth analysis of the degree of disorder in the material. Strong electronic correlations in rare-earth nickelates make them prone to unconventional behaviour but extrinsic effects hamper the interpretation of data. Guo et al. show that apparent non-Fermi liquid transport in NdNiO3 is tuned by strain and disorder, suggesting a more conventional origin.
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20
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De Nardis J, Medenjak M, Karrasch C, Ilievski E. Universality Classes of Spin Transport in One-Dimensional Isotropic Magnets: The Onset of Logarithmic Anomalies. PHYSICAL REVIEW LETTERS 2020; 124:210605. [PMID: 32530698 DOI: 10.1103/physrevlett.124.210605] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 05/07/2020] [Indexed: 06/11/2023]
Abstract
We report a systematic study of finite-temperature spin transport in quantum and classical one-dimensional magnets with isotropic spin interactions, including both integrable and nonintegrable models. Employing a phenomenological framework based on a generalized Burgers' equation in a time-dependent stochastic environment, we identify four different universality classes of spin fluctuations. These comprise, aside from normal spin diffusion, three types of superdiffusive transport: the Kardar-Parisi-Zhang universality class and two distinct types of anomalous diffusion with multiplicative logarithmic corrections. Our predictions are supported by extensive numerical simulations on various examples of quantum and classical chains. Contrary to common belief, we demonstrate that even nonintegrable spin chains can display a diverging spin diffusion constant at finite temperatures.
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Affiliation(s)
- Jacopo De Nardis
- Department of Physics and Astronomy, University of Ghent, Krijgslaan 281, 9000 Gent, Belgium
| | - Marko Medenjak
- Institut de Physique Théorique Philippe Meyer, École Normale Supérieure, PSL University, Sorbonne Universités, CNRS, 75005 Paris, France
| | - Christoph Karrasch
- Technische Universität Braunschweig, Institut für Mathematische Physik, Mendelssohnstraße 3, 38106 Braunschweig, Germany
| | - Enej Ilievski
- Faculty for Mathematics and Physics, University of Ljubljana, Jadranska ulica 19, 1000 Ljubljana, Slovenia
- Institute for Theoretical Physics Amsterdam and Delta Institute for Theoretical Physics, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, Netherlands
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21
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Wang Y, Walter E, Lee SSB, Stadler KM, von Delft J, Weichselbaum A, Kotliar G. Global Phase Diagram of a Spin-Orbital Kondo Impurity Model and the Suppression of Fermi-Liquid Scale. PHYSICAL REVIEW LETTERS 2020; 124:136406. [PMID: 32302177 DOI: 10.1103/physrevlett.124.136406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Accepted: 02/28/2020] [Indexed: 06/11/2023]
Abstract
Many correlated metallic materials are described by Landau Fermi-liquid theory at low energies, but for Hund metals the Fermi-liquid coherence scale T_{FL} is found to be surprisingly small. In this Letter, we study the simplest impurity model relevant for Hund metals, the three-channel spin-orbital Kondo model, using the numerical renormalization group (NRG) method and compute its global phase diagram. In this framework, T_{FL} becomes arbitrarily small close to two new quantum critical points that we identify by tuning the spin or spin-orbital Kondo couplings into the ferromagnetic regimes. We find quantum phase transitions to a singular Fermi-liquid or a novel non-Fermi-liquid phase. The new non-Fermi-liquid phase shows frustrated behavior involving alternating overscreenings in spin and orbital sectors, with universal power laws in the spin (ω^{-1/5}), orbital (ω^{1/5}) and spin-orbital (ω^{1}) dynamical susceptibilities. These power laws, and the NRG eigenlevel spectra, can be fully understood using conformal field theory arguments, which also clarify the nature of the non-Fermi-liquid phase.
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Affiliation(s)
- Y Wang
- Department of Condensed Matter Physics and Materials Science, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - E Walter
- Arnold Sommerfeld Center for Theoretical Physics, Center for NanoScience, and Munich Center for Quantum Science and Technology, Ludwig-Maximilians-Universität München, 80333 Munich, Germany
| | - S-S B Lee
- Arnold Sommerfeld Center for Theoretical Physics, Center for NanoScience, and Munich Center for Quantum Science and Technology, Ludwig-Maximilians-Universität München, 80333 Munich, Germany
| | - K M Stadler
- Arnold Sommerfeld Center for Theoretical Physics, Center for NanoScience, and Munich Center for Quantum Science and Technology, Ludwig-Maximilians-Universität München, 80333 Munich, Germany
| | - J von Delft
- Arnold Sommerfeld Center for Theoretical Physics, Center for NanoScience, and Munich Center for Quantum Science and Technology, Ludwig-Maximilians-Universität München, 80333 Munich, Germany
| | - A Weichselbaum
- Department of Condensed Matter Physics and Materials Science, Brookhaven National Laboratory, Upton, New York 11973, USA
- Arnold Sommerfeld Center for Theoretical Physics, Center for NanoScience, and Munich Center for Quantum Science and Technology, Ludwig-Maximilians-Universität München, 80333 Munich, Germany
| | - G Kotliar
- Department of Condensed Matter Physics and Materials Science, Brookhaven National Laboratory, Upton, New York 11973, USA
- Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08856, USA
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22
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Gupta R, Bhatti IN, Pramanik AK. Site dilution and charge disorder effect on physical properties in SrRu 1-x Ga x O 3. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:035803. [PMID: 31574499 DOI: 10.1088/1361-648x/ab49a1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Here, we report an evolution of structural, magnetic and transport behavior in doped SrRu1-x Ga x O3 (x [Formula: see text] 0.2). The nonmagnetic dopant Ga3+ (3d 10) not only acts for magnetic site dilution in SrRuO3 but also modifies the Ru charge state and electronic density. Our studies show that Ga3+ substitution does not affect the original orthorhombic- Pbnm structure of SrRuO3 which is due to its matching ionic radii with Ru4+ . However, Ga3+ has a substantial effect on the magnetic behavior of SrRuO3 where it decreases both magnetic moment as well as magnetic transition temperature [Formula: see text]. Further, this dilution induces Griffiths phase behavior across [Formula: see text] and cluster-glass behavior at low temperature with higher concentration of doping. The magnetic critical exponent [Formula: see text] increases with x due to this site dilution effect. The Ga3+ induces an insulating state in SrRuO3 with x > 0.05. The charge transport in paramagnetic as well as in insulating state of samples can be well described with Mott's modified variable-range-hopping model. The metallic charge transport just below [Formula: see text] in SrRuO3 obeys Fermi liquid behavior which breaks down at low temperature. We further find a correlation between field dependent magnetoresistance and magnetization through power-law behavior over the series.
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Affiliation(s)
- Renu Gupta
- School of Physical Sciences, Jawaharlal Nehru University, New Delhi 110067, India
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23
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Huang EW, Sheppard R, Moritz B, Devereaux TP. Strange metallicity in the doped Hubbard model. Science 2019; 366:987-990. [DOI: 10.1126/science.aau7063] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2018] [Revised: 12/28/2018] [Accepted: 10/25/2019] [Indexed: 11/02/2022]
Abstract
Strange or bad metallic transport, defined by incompatibility with the conventional quasiparticle picture, is a theme common to many strongly correlated materials, including high-temperature superconductors. The Hubbard model represents a minimal starting point for modeling strongly correlated systems. Here we demonstrate strange metallic transport in the doped two-dimensional Hubbard model using determinantal quantum Monte Carlo calculations. Over a wide range of doping, we observe resistivities exceeding the Mott-Ioffe-Regel limit with linear temperature dependence. The temperatures of our calculations extend to as low as 1/40 of the noninteracting bandwidth, placing our findings in the degenerate regime relevant to experimental observations of strange metallicity. Our results provide a foundation for connecting theories of strange metals to models of strongly correlated materials.
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24
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Behnia K, Kapitulnik A. A lower bound to the thermal diffusivity of insulators. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:405702. [PMID: 31252425 DOI: 10.1088/1361-648x/ab2db6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
It has been known for decades that thermal conductivity of insulating crystals becomes proportional to the inverse of temperature when the latter is comparable to, or higher than, the Debye temperature. This behavior has been understood as resulting from Umklapp scattering among phonons. We put under scrutiny the magnitude of the thermal diffusion constant in this regime and find that it does not fall below a threshold set by the square of sound velocity times the Planckian time ([Formula: see text]). The conclusion, based on scrutinizing the ratio in cubic crystals with high thermal resistivity, appears to hold even in glasses where Umklapp events are not conceivable. Explaining this boundary, reminiscent of a recently-noticed limit for charge transport in metals, is a challenge to theory.
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Affiliation(s)
- Kamran Behnia
- Laboratoire Physique et Etude de Matériaux (CNRS-Sorbonne Université), ESPCI Paris, PSL Research University, 75005 Paris, France. II. Physikalisches Institut, Universität zu Köln, 50937 Köln, Germany
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25
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Thermalization and possible signatures of quantum chaos in complex crystalline materials. Proc Natl Acad Sci U S A 2019; 116:19869-19874. [PMID: 31515452 DOI: 10.1073/pnas.1910131116] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Analyses of thermal diffusivity data on complex insulators and on strongly correlated electron systems hosted in similar complex crystal structures suggest that quantum chaos is a good description for thermalization processes in these systems, particularly in the high-temperature regime where the many phonon bands and their interactions dominate the thermal transport. Here we observe that for these systems diffusive thermal transport is controlled by a universal Planckian timescale [Formula: see text] and a unique velocity [Formula: see text] Specifically, [Formula: see text] for complex insulators, and [Formula: see text] in the presence of strongly correlated itinerant electrons ([Formula: see text] and [Formula: see text] are the phonon and electron velocities, respectively). For the complex correlated electron systems we further show that charge diffusivity, while also reaching the Planckian relaxation bound, is largely dominated by the Fermi velocity of the electrons, hence suggesting that it is only the thermal (energy) diffusivity that describes chaos diffusivity.
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26
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Cai W, Lin W, Li LH, Malliakas CD, Zhang R, Groesbeck M, Bao JK, Zhang D, Sterer E, Kanatzidis MG, Deemyad S. Pressure-Induced Superconductivity and Flattened Se 6 Rings in the Wide Band Gap Semiconductor Cu 2I 2Se 6. J Am Chem Soc 2019; 141:15174-15182. [PMID: 31480843 DOI: 10.1021/jacs.9b06794] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The two major classes of unconventional superconductors, cuprates and Fe-based superconductors, have magnetic parent compounds, are layered, and generally feature square-lattice symmetry. We report the discovery of pressure-induced superconductivity in a nonmagnetic and wide band gap 1.95 eV semiconductor, Cu2I2Se6, with a unique anisotropic structure composed of two types of distinct molecules: Se6 rings and Cu2I2 dimers, which are linked in a three-dimensional framework. Cu2I2Se6 exhibits a concurrent pressure-induced metallization and superconductivity at ∼21.0 GPa with critical temperature (Tc) of ∼2.8 K. The Tc monotonically increases within the range of our study reaching ∼9.0 K around 41.0 GPa. These observations coincide with unprecedented chair-to-planar conformational changes of Se6 rings, an abrupt decrease along the c-axis, and negative compression within the ab plane during the phase transition. DFT calculations demonstrate that the flattened Se6 rings within the CuSe layer create a high density of states at the Fermi level. The unique structural features of Cu2I2Se6 imply that superconductivity may emerge in anisotropic Cu-containing materials without square-lattice geometry and magnetic order in the parent compound.
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Affiliation(s)
- Weizhao Cai
- Department of Physics and Astronomy , University of Utah , Salt Lake City , Utah 84112 , United States
| | - Wenwen Lin
- Materials Science Division , Argonne National Laboratory , Argonne , Illinois 60439 , United States
| | - Long-Hua Li
- School of Chemistry and Chemical Engineering , Jiangsu University , Zhenjiang 212013 , China
| | - Christos D Malliakas
- Department of Chemistry , Northwestern University , Evanston , Illinois 60208 , United States
| | - Rong Zhang
- Department of Physics and Astronomy , University of Utah , Salt Lake City , Utah 84112 , United States
| | - Matthew Groesbeck
- Department of Physics and Astronomy , University of Utah , Salt Lake City , Utah 84112 , United States
| | - Jin-Ke Bao
- Materials Science Division , Argonne National Laboratory , Argonne , Illinois 60439 , United States
| | - Dongzhou Zhang
- PX2, Hawaii Institute of Geophysics and Planetology , University of Hawaii at Manoa , Honolulu , Hawaii 96822 , United States
| | - Eran Sterer
- Department of Physics and Astronomy , University of Utah , Salt Lake City , Utah 84112 , United States.,Department of Physics , Nuclear Research Center , Negev, P.O. Box 9001, Beer-Sheva 84190 , Israel
| | - Mercouri G Kanatzidis
- Materials Science Division , Argonne National Laboratory , Argonne , Illinois 60439 , United States.,Department of Chemistry , Northwestern University , Evanston , Illinois 60208 , United States
| | - Shanti Deemyad
- Department of Physics and Astronomy , University of Utah , Salt Lake City , Utah 84112 , United States
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27
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Mousatov CH, Esterlis I, Hartnoll SA. Bad Metallic Transport in a Modified Hubbard Model. PHYSICAL REVIEW LETTERS 2019; 122:186601. [PMID: 31144908 DOI: 10.1103/physrevlett.122.186601] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Revised: 12/09/2018] [Indexed: 06/09/2023]
Abstract
Strongly correlated metals often display anomalous transport, including T-linear resistivity above the Mott-Ioffe-Regel limit. We introduce a tractable microscopic model for bad metals, by restoring in the well-known Hubbard model-with hopping t and on-site repulsion U-a "screened Coulomb" interaction between charge densities that decays exponentially with spatial separation. This interaction lifts the extensive degeneracy in the spectrum of the t=0 Hubbard model, allowing us to fully characterize the small t electric, thermal, and thermoelectric transport in our strongly correlated model. Throughout the phase diagram we observe T-linear resistivity above the Mott-Ioffe-Regel limit, together with strong violation of the Wiedemann-Franz law and a large thermopower that can undergo sign change.
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Affiliation(s)
- Connie H Mousatov
- Department of Physics, Stanford University, Stanford, California 94305, USA
| | - Ilya Esterlis
- Department of Physics, Stanford University, Stanford, California 94305, USA
| | - Sean A Hartnoll
- Department of Physics, Stanford University, Stanford, California 94305, USA
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28
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Abstract
Electrical current in conventional metals is carried by electrons that retain their individual character. Bad metals, such as the normal state of some high-temperature superconductors, violate this scenario, and the complete picture for their behavior remains unresolved. Here, we report phenomena consistent with bad-metal behaviour in an optical-lattice Hubbard model by measuring the transport lifetime for a mass current excited by stimulated Raman transitions. We demonstrate incompatibility with weak-scattering theory and key characteristics of bad metals: anomalous resistivity scaling consistent with T-linear behavior, the onset of incoherent transport, and the approach to the Mott–Ioffe–Regel limit. Our work demonstrates a direct method for determining the transport lifetime, which is critical to theory but difficult to measure in materials, and exposes minimal ingredients for bad-metal behavior. The origin of bad-metal resistivity is a long-standing problem for condensed matter physics. Here the authors show anomalous resistivity, transport lifetime, and relaxation dynamics consistent with bad-metal behavior over a wide range of temperature for fermionic potassium atoms in optical lattices.
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29
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Banerjee A, Mohapatra A, Ganesan R, Kumar PSA. Restoring Superconductivity in the Quantum Metal Phase of NbSe 2 Using Dissipative Coupling. NANO LETTERS 2019; 19:1625-1631. [PMID: 30735619 DOI: 10.1021/acs.nanolett.8b04538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Localization arguments forbid the appearance of a metallic ground state in two dimensions. Yet, a large variety of disordered superconductors are known to manifest an anomalous metal phase in the zero temperature limit. While previous observations were confined to noncrystalline "dirty" superconductors, the recent observation of the so-called Bose metal phase in crystalline thin flakes of NbSe2 has sparked off intense debate. While the exact nature of this phase remains unknown, it is thought that quantum fluctuations play a decisive role in Bose metal physics. In this work, we study the response of the anomalous metal phase in thin flakes of NbSe2 to dissipative coupling. We evince a dramatic quenching of the Bose metal phase when dissipative coupling is strong, fully restoring a zero resistance superconducting state in the entire region of the magnetic field (H)-temperature (T) phase diagram where the Bose metal phase is otherwise observed. The suppression of the Bose metal phase by dissipative coupling is possible only in a quantum system where dissipation can directly affect system thermodynamics. Our observation of a dissipative phase transition in two-dimensional NbSe2 firmly establishes the quantum nature of the anomalous metal phase in this class of "clean" superconductors.
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Affiliation(s)
- Abhishek Banerjee
- Department of Physics , Indian Institute of Science , Bengaluru 560012 , India
| | - Abhinab Mohapatra
- Department of Physics , Indian Institute of Science , Bengaluru 560012 , India
| | - R Ganesan
- Department of Physics , Indian Institute of Science , Bengaluru 560012 , India
| | - P S Anil Kumar
- Department of Physics , Indian Institute of Science , Bengaluru 560012 , India
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30
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Chen-Lin X, Delacrétaz LV, Hartnoll SA. Theory of Diffusive Fluctuations. PHYSICAL REVIEW LETTERS 2019; 122:091602. [PMID: 30932534 DOI: 10.1103/physrevlett.122.091602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Indexed: 06/09/2023]
Abstract
The recently developed effective field theory of fluctuations around thermal equilibrium is used to compute late-time correlation functions of conserved densities. Specializing to systems with a single conservation law, we find that the diffusive pole is shifted in the presence of nonlinear hydrodynamic self-interactions, and that the density-density Green's function acquires a branch point halfway to the diffusive pole, at frequency ω=-(i/2)Dk^{2}. We discuss the relevance of diffusive fluctuations for strongly correlated transport in condensed matter and cold atomic systems.
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Affiliation(s)
- Xinyi Chen-Lin
- Department of Physics, Stanford University, Stanford, California 94305-4060, USA
| | - Luca V Delacrétaz
- Department of Physics, Stanford University, Stanford, California 94305-4060, USA
| | - Sean A Hartnoll
- Department of Physics, Stanford University, Stanford, California 94305-4060, USA
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31
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Mahmood F, He X, Božović I, Armitage NP. Locating the Missing Superconducting Electrons in the Overdoped Cuprates La_{2-x}Sr_{x}CuO_{4}. PHYSICAL REVIEW LETTERS 2019; 122:027003. [PMID: 30720319 DOI: 10.1103/physrevlett.122.027003] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Revised: 12/11/2018] [Indexed: 06/09/2023]
Abstract
Overdoped high-temperature cuprate superconductors have often been understood within the standard BCS framework of superconductivity. However, measurements in a variety of overdoped cuprates indicate that the superfluid density is much smaller than expected from BCS theory and decreases smoothly to zero as the doping is increased. Here, we combine time-domain THz spectroscopy with kHz range mutual inductance measurements on the same overdoped La_{2-x}Sr_{x}CuO_{4} films to determine the total, superfluid, and uncondensed spectral weight as a function of doping. A significant fraction of the carriers remains uncondensed in a wide Drude-like peak as T→0, while the superfluid density remains linear in temperature. These observations are seemingly inconsistent with existing, realistic theories of impurity scattering suppressing the superfluid density in a BCS-like d-wave superconductor. Our large measurement frequency range gives us a unique look at the low frequency spectral weight distribution, which may suggest the presence of quantum phase fluctuations as the critical doping is approached.
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Affiliation(s)
- Fahad Mahmood
- The Institute for Quantum Matter, Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, Maryland 21218 USA
| | - Xi He
- Brookhaven National Laboratory, Upton, New York 11973, USA
- Applied Physics Department, Yale University, New Haven, Connecticut 06520, USA
| | - Ivan Božović
- Brookhaven National Laboratory, Upton, New York 11973, USA
- Applied Physics Department, Yale University, New Haven, Connecticut 06520, USA
| | - N P Armitage
- The Institute for Quantum Matter, Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, Maryland 21218 USA
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32
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Huang J, Zhao L, Li C, Gao Q, Liu J, Hu Y, Xu Y, Cai Y, Wu D, Ding Y, Hu C, Zhou H, Dong X, Liu G, Wang Q, Zhang S, Wang Z, Zhang F, Yang F, Peng Q, Xu Z, Chen C, Zhou X. Emergence of superconductivity from fully incoherent normal state in an iron-based superconductor (Ba 0.6K 0.4)Fe 2As 2. Sci Bull (Beijing) 2019; 64:11-19. [PMID: 36659518 DOI: 10.1016/j.scib.2018.11.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Revised: 11/24/2018] [Accepted: 11/26/2018] [Indexed: 01/21/2023]
Abstract
In unconventional superconductors, it is generally believed that understanding the physical properties of the normal state is a pre-requisite for understanding the superconductivity mechanism. In conventional superconductors like niobium or lead, the normal state is a Fermi liquid with a well-defined Fermi surface and well-defined quasipartcles along the Fermi surface. Superconductivity is realized in this case by the Fermi surface instability in the superconducting state and the formation and condensation of the electron pairs (Cooper pairing). The high temperature cuprate superconductors, on the other hand, represent another extreme case that superconductivity can be realized in the underdoped region where there is neither well-defined Fermi surface due to the pseudogap formation nor quasiparticles near the antinodal regions in the normal state. Here we report a novel scenario that superconductivity is realized in a system with well-defined Fermi surface but without quasiparticles along the Fermi surface in the normal state. High resolution laser-based angle-resolved photoemission measurements have been performed on an optimally-doped iron-based superconductor (Ba0.6K0.4)Fe2As2. We find that, while sharp superconducting coherence peaks emerge in the superconducting state on the hole-like Fermi surface sheets, no quasiparticle peak is present in the normal state. Its electronic behaviours deviate strongly from a Fermi liquid system. The superconducting gap of such a system exhibits an unusual temperature dependence that it is nearly a constant in the superconducting state and abruptly closes at Tc. These observations have provided a new platform to study unconventional superconductivity in a non-Fermi liquid system.
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Affiliation(s)
- Jianwei Huang
- 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
| | - Lin Zhao
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
| | - Cong Li
- 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
| | - Qiang Gao
- 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
| | - Jing Liu
- 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
| | - Yong Hu
- 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
| | - Yu Xu
- 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
| | - Yongqing Cai
- 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
| | - Dingsong Wu
- 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
| | - Ying Ding
- 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
| | - Cheng Hu
- 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
| | - Huaxue Zhou
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Xiaoli Dong
- 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
| | - Guodong Liu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Qingyan Wang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Shenjin Zhang
- Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Zhimin Wang
- Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Fengfeng Zhang
- Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Feng Yang
- Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Qinjun Peng
- Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Zuyan Xu
- Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Chuangtian Chen
- Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Xingjiang Zhou
- 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; Songshan Lake Materials Laboratory, Dongguan 523808, China; Collaborative Innovation Center of Quantum Matter, Beijing 100871, China.
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33
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Kemmler R, Hübner R, Löhle A, Neubauer D, Voloshenko I, Schoop LM, Dressel M, Pronin AV. Free-carrier dynamics in Au 2Pb probed by optical conductivity measurements. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:485403. [PMID: 30418951 DOI: 10.1088/1361-648x/aae7b1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We measured the optical reflectivity of the Dirac material Au2Pb in a broad frequency range (30-48 000 cm-1) for temperatures between 9 and 300 K. The optical conductivity, computed from the reflectivity, is dominated by free-carrier contributions from topologically trivial bulk bands at all temperatures. The temperature-independent total plasma frequency of these carriers is [Formula: see text] eV. Overall, optical response of Au2Pb is typically metallic with no signs of localization and bad-metal behavior.
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Affiliation(s)
- R Kemmler
- 1. Physikalisches Institut, Universität Stuttgart, 70569 Stuttgart, Germany
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34
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Patel AA, Lawler MJ, Kim EA. Coherent Superconductivity with a Large Gap Ratio from Incoherent Metals. PHYSICAL REVIEW LETTERS 2018; 121:187001. [PMID: 30444391 DOI: 10.1103/physrevlett.121.187001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Indexed: 06/09/2023]
Abstract
A mysterious incoherent metallic (IM) normal state with T-linear resistivity is ubiquitous among strongly correlated superconductors. Recent progress with microscopic models exhibiting IM transport has presented the opportunity for us to study new models that exhibit direct transitions into a superconducting state out of IM states within the framework of connected Sachdev-Ye-Kitaev "quantum dots." Here, local Sachdev-Ye-Kitaev interactions within a dot produce IM transport in the normal state, while local attractive interactions drive superconductivity. Through explicit calculations, we find two features of superconductivity arising from an IM normal state. First, despite the absence of quasiparticles in the normal state, the superconducting state still exhibits coherent superfluid transport. Second, the nonquasiparticle nature of the IM Green's functions produces a large enhancement in the ratio of the zero-temperature superconducting gap Δ and transition temperature T_{SC}, 2Δ/T_{SC}, with respect to its BCS value of 3.53.
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Affiliation(s)
- Aavishkar A Patel
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
- Kavli Institute for Theoretical Physics, University of California, Santa Barbara, California 93106-4030, USA
| | - Michael J Lawler
- Department of Physics, Cornell University, Ithaca, New York 14853, USA
- Department of Physics, Binghamton University, Vestal, New York 13850, USA
| | - Eun-Ah Kim
- Department of Physics, Cornell University, Ithaca, New York 14853, USA
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35
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Giraldo-Gallo P, Galvis JA, Stegen Z, Modic KA, Balakirev FF, Betts JB, Lian X, Moir C, Riggs SC, Wu J, Bollinger AT, He X, Božović I, Ramshaw BJ, McDonald RD, Boebinger GS, Shekhter A. Scale-invariant magnetoresistance in a cuprate superconductor. Science 2018; 361:479-481. [PMID: 30072535 DOI: 10.1126/science.aan3178] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 05/31/2018] [Indexed: 11/02/2022]
Abstract
The anomalous metallic state in the high-temperature superconducting cuprates is masked by superconductivity near a quantum critical point. Applying high magnetic fields to suppress superconductivity has enabled detailed studies of the normal state, yet the direct effect of strong magnetic fields on the metallic state is poorly understood. We report the high-field magnetoresistance of thin-film La2-x Sr x CuO4 cuprate in the vicinity of the critical doping, 0.161 ≤ p ≤ 0.190. We find that the metallic state exposed by suppressing superconductivity is characterized by magnetoresistance that is linear in magnetic fields up to 80 tesla. The magnitude of the linear-in-field resistivity mirrors the magnitude and doping evolution of the well-known linear-in-temperature resistivity that has been associated with quantum criticality in high-temperature superconductors.
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Affiliation(s)
- P Giraldo-Gallo
- National High Magnetic Field Laboratory (NHMFL), Florida State University, Tallahassee, FL 32310, USA.,Department of Physics, Universidad de Los Andes, Bogotá 111711, Colombia
| | - J A Galvis
- National High Magnetic Field Laboratory (NHMFL), Florida State University, Tallahassee, FL 32310, USA.,Departamento de Ciencias Naturales, Facultad de Ingeniería y Ciencias Básicas, Universidad Central, Bogotá 110311, Colombia
| | - Z Stegen
- National High Magnetic Field Laboratory (NHMFL), Florida State University, Tallahassee, FL 32310, USA.,Department of Physics, Florida State University, Tallahassee, FL 32310, USA
| | - K A Modic
- Max Planck Institute for Chemical Physics of Solids, D-01187 Dresden, Germany
| | - F F Balakirev
- Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - J B Betts
- Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - X Lian
- National High Magnetic Field Laboratory (NHMFL), Florida State University, Tallahassee, FL 32310, USA.,Department of Physics, Florida State University, Tallahassee, FL 32310, USA
| | - C Moir
- National High Magnetic Field Laboratory (NHMFL), Florida State University, Tallahassee, FL 32310, USA.,Department of Physics, Florida State University, Tallahassee, FL 32310, USA
| | - S C Riggs
- National High Magnetic Field Laboratory (NHMFL), Florida State University, Tallahassee, FL 32310, USA
| | - J Wu
- Brookhaven National Laboratory (BNL), Upton, NY 11973, USA
| | - A T Bollinger
- Brookhaven National Laboratory (BNL), Upton, NY 11973, USA
| | - X He
- Brookhaven National Laboratory (BNL), Upton, NY 11973, USA.,Applied Physics Department, Yale University, New Haven, CT 06520, USA
| | - I Božović
- Brookhaven National Laboratory (BNL), Upton, NY 11973, USA.,Applied Physics Department, Yale University, New Haven, CT 06520, USA
| | - B J Ramshaw
- Los Alamos National Laboratory, Los Alamos, NM 87545, USA.,Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, NY 14853, USA
| | - R D McDonald
- Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - G S Boebinger
- National High Magnetic Field Laboratory (NHMFL), Florida State University, Tallahassee, FL 32310, USA.,Department of Physics, Florida State University, Tallahassee, FL 32310, USA
| | - A Shekhter
- National High Magnetic Field Laboratory (NHMFL), Florida State University, Tallahassee, FL 32310, USA.
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36
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Hohenadler M, Assaad FF. Fractionalized Metal in a Falicov-Kimball Model. PHYSICAL REVIEW LETTERS 2018; 121:086601. [PMID: 30192610 DOI: 10.1103/physrevlett.121.086601] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Indexed: 06/08/2023]
Abstract
Quantum Monte Carlo simulations reveal an exotic metallic phase with a single-particle gap but gapless spin and charge excitations and a nonsaturating resistivity in a two-dimensional SU(2) Falicov-Kimball model. An exact duality between this model and an unconstrained slave-spin theory leads to a classification of the phase as a fractionalized or orthogonal metal whose low-energy excitations have different quantum numbers than the original electrons. Whereas the fractionalized metal corresponds to the regime of disordered slave spins, the regime of ordered slave spins is a Fermi liquid. At a critical temperature, an Ising phase transition to a spontaneously generated constrained slave-spin theory of the Hubbard model is observed.
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Affiliation(s)
- Martin Hohenadler
- Institut für Theoretische Physik und Astrophysik, Universität Würzburg, 97074 Würzburg, Germany
| | - Fakher F Assaad
- Institut für Theoretische Physik und Astrophysik, Universität Würzburg, 97074 Würzburg, Germany
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37
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Stemmer S, Allen SJ. Non-Fermi liquids in oxide heterostructures. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2018; 81:062502. [PMID: 29651990 DOI: 10.1088/1361-6633/aabdfa] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Understanding the anomalous transport properties of strongly correlated materials is one of the most formidable challenges in condensed matter physics. For example, one encounters metal-insulator transitions, deviations from Landau Fermi liquid behavior, longitudinal and Hall scattering rate separation, a pseudogap phase, and bad metal behavior. These properties have been studied extensively in bulk materials, such as the unconventional superconductors and heavy fermion systems. Oxide heterostructures have recently emerged as new platforms to probe, control, and understand strong correlation phenomena. This article focuses on unconventional transport phenomena in oxide thin film systems. We use specific systems as examples, namely charge carriers in SrTiO3 layers and interfaces with SrTiO3, and strained rare earth nickelate thin films. While doped SrTiO3 layers appear to be a well behaved, though complex, electron gas or Fermi liquid, the rare earth nickelates are a highly correlated electron system that may be classified as a non-Fermi liquid. We discuss insights into the underlying physics that can be gained from studying the emergence of non-Fermi liquid behavior as a function of the heterostructure parameters. We also discuss the role of lattice symmetry and disorder in phenomena such as metal-insulator transitions in strongly correlated heterostructures.
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Affiliation(s)
- Susanne Stemmer
- Materials Department, University of California, Santa Barbara, CA 93106-5050, United States of America
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38
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Sherman A. Influence of spin and charge fluctuations on spectra of the two-dimensional Hubbard model. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:195601. [PMID: 29583129 DOI: 10.1088/1361-648x/aaba0e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The influence of spin and charge fluctuations on spectra of the two-dimensional fermionic Hubbard model is considered using the strong coupling diagram technique. Infinite sequences of diagrams containing ladder inserts, which describe the interaction of electrons with these fluctuations, are summed, and obtained equations are self-consistently solved for the ranges of Hubbard repulsions [Formula: see text], temperatures [Formula: see text] and electron concentrations [Formula: see text] with t the intersite hopping constant. For all considered U the system exhibits a transition to the long-range antiferromagnetic order at [Formula: see text]. At the same time no indication of charge ordering is observed. Obtained solutions agree satisfactorily with results of other approaches and obey moments sum rules. In the considered region of the U-T plane, the curve separating metallic solutions passes from [Formula: see text] at the highest temperatures to U = 2t at [Formula: see text] for half-filling. If only short-range fluctuations are allowed for the remaining part of this region is occupied by insulating solutions. Taking into account long-range fluctuations leads to strengthening of maxima tails, which transform a part of insulating solutions into bad-metal states. For low T, obtained results allow us to trace the gradual transition from the regime of strong correlations with the pronounced four-band structure and well-defined Mott gap for [Formula: see text] to the Slater regime of weak correlations with the spectral intensity having a dip along the boundary of the magnetic Brillouin zone due to an antiferromagnetic ordering for [Formula: see text]. For [Formula: see text] and [Formula: see text] doping leads to the occurrence of a pseudogap near the Fermi level, which is a consequence of the splitting out of a narrow band from a Hubbard subband. Obtained spectra feature waterfalls and Fermi arcs, which are similar to those observed in hole-doped cuprates.
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Affiliation(s)
- A Sherman
- Institute of Physics, University of Tartu, W. Ostwaldi Str 1, 50411 Tartu, Estonia
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39
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Song XY, Jian CM, Balents L. Strongly Correlated Metal Built from Sachdev-Ye-Kitaev Models. PHYSICAL REVIEW LETTERS 2017; 119:216601. [PMID: 29219415 DOI: 10.1103/physrevlett.119.216601] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Indexed: 06/07/2023]
Abstract
Prominent systems like the high-T_{c} cuprates and heavy fermions display intriguing features going beyond the quasiparticle description. The Sachdev-Ye-Kitaev (SYK) model describes a (0+1)D quantum cluster with random all-to-all four-fermion interactions among N fermion modes which becomes exactly solvable as N→∞, exhibiting a zero-dimensional non-Fermi-liquid with emergent conformal symmetry and complete absence of quasiparticles. Here we study a lattice of complex-fermion SYK dots with random intersite quadratic hopping. Combining the imaginary time path integral with real time path integral formulation, we obtain a heavy Fermi liquid to incoherent metal crossover in full detail, including thermodynamics, low temperature Landau quasiparticle interactions, and both electrical and thermal conductivity at all scales. We find linear in temperature resistivity in the incoherent regime, and a Lorentz ratio L≡(κρ/T) varies between two universal values as a function of temperature. Our work exemplifies an analytically controlled study of a strongly correlated metal.
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Affiliation(s)
- Xue-Yang Song
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
- Kavli Institute of Theoretical Physics, University of California, Santa Barbara, California 93106, USA
| | - Chao-Ming Jian
- Kavli Institute of Theoretical Physics, University of California, Santa Barbara, California 93106, USA
- Station Q, Microsoft Research, Santa Barbara, California 93106-6105, USA
| | - Leon Balents
- Kavli Institute of Theoretical Physics, University of California, Santa Barbara, California 93106, USA
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40
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Abstract
We obtain a rigorous upper bound on the resistivity [Formula: see text] of an electron fluid whose electronic mean free path is short compared with the scale of spatial inhomogeneities. When such a hydrodynamic electron fluid supports a nonthermal diffusion process-such as an imbalance mode between different bands-we show that the resistivity bound becomes [Formula: see text] The coefficient [Formula: see text] is independent of temperature and inhomogeneity lengthscale, and [Formula: see text] is a microscopic momentum-preserving scattering rate. In this way, we obtain a unified mechanism-without umklapp-for [Formula: see text] in a Fermi liquid and the crossover to [Formula: see text] in quantum critical regimes. This behavior is widely observed in transition metal oxides, organic metals, pnictides, and heavy fermion compounds and has presented a long-standing challenge to transport theory. Our hydrodynamic bound allows phonon contributions to diffusion constants, including thermal diffusion, to directly affect the electrical resistivity.
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41
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Hartman T, Hartnoll SA, Mahajan R. Upper Bound on Diffusivity. PHYSICAL REVIEW LETTERS 2017; 119:141601. [PMID: 29053285 DOI: 10.1103/physrevlett.119.141601] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Indexed: 06/07/2023]
Abstract
The linear growth of operators in local quantum systems leads to an effective light cone even if the system is nonrelativistic. We show that the consistency of diffusive transport with this light cone places an upper bound on the diffusivity: D≲v^{2}τ_{eq}. The operator growth velocity v defines the light cone, and τ_{eq} is the local equilibration time scale, beyond which the dynamics of conserved densities is diffusive. We verify that the bound is obeyed in various weakly and strongly interacting theories. In holographic models, this bound establishes a relation between the hydrodynamic and leading nonhydrodynamic quasinormal modes of planar black holes. Our bound relates transport data-including the electrical resistivity and the shear viscosity-to the local equilibration time, even in the absence of a quasiparticle description. In this way, the bound sheds light on the observed T-linear resistivity of many unconventional metals, the shear viscosity of the quark-gluon plasma, and the spin transport of unitary fermions.
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Affiliation(s)
- Thomas Hartman
- Department of Physics, Cornell University, Ithaca, New York 14850, USA
| | - Sean A Hartnoll
- Department of Physics, Stanford University, Stanford, California 94305, USA
| | - Raghu Mahajan
- Department of Physics, Stanford University, Stanford, California 94305, USA
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42
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Tuning electromagnetic properties of SrRuO 3 epitaxial thin films via atomic control of cation vacancies. Sci Rep 2017; 7:11583. [PMID: 28912587 PMCID: PMC5599527 DOI: 10.1038/s41598-017-11856-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Accepted: 08/31/2017] [Indexed: 11/15/2022] Open
Abstract
Elemental defect in transition metal oxides is an important and intriguing subject that result in modifications in variety of physical properties including atomic and electronic structure, optical and magnetic properties. Understanding the formation of elemental vacancies and their influence on different physical properties is essential in studying the complex oxide thin films. In this study, we investigated the physical properties of epitaxial SrRuO3 thin films by systematically manipulating cation and/or oxygen vacancies, via changing the oxygen partial pressure (P(O2)) during the pulsed laser epitaxy (PLE) growth. Ru vacancies in the low-P(O2)-grown SrRuO3 thin films induce lattice expansion with the suppression of the ferromagnetic TC down to ~120 K. Sr vacancies also disturb the ferromagnetic ordering, even though Sr is not a magnetic element. Our results indicate that both A and B cation vacancies in an ABO3 perovskite can be systematically engineered via PLE, and the structural, electrical, and magnetic properties can be tailored accordingly.
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43
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Autieri C, Cuono G, Forte F, Noce C. Low energy bands and transport properties of chromium arsenide. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:224004. [PMID: 28379840 DOI: 10.1088/1361-648x/aa6b98] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We apply a method that combines the tight-binding approximation and the Löwdin down-folding procedure to evaluate the electronic band structure of the newly discovered pressure-induced superconductor CrAs. By integrating out all low-lying arsenic degrees of freedom, we derive an effective Hamiltonian model describing the Cr d bands near the Fermi level. We calculate and make predictions for the energy spectra, the Fermi surface, the density of states and transport and magnetic properties of this compound. Our results are consistent with local-density approximation calculations and they also show good agreement with available experimental data for resistivity and the Cr magnetic moment.
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Affiliation(s)
- Carmine Autieri
- Consiglio Nazionale delle Ricerche CNR-SPIN, UOS L'Aquila, Sede Temporanea di Chieti, I-66100 Chieti, Italy
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44
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Abstract
The thermal diffusivity in the [Formula: see text] plane of underdoped YBCO crystals is measured by means of a local optical technique in the temperature range of 25-300 K. The phase delay between a point heat source and a set of detection points around it allows for high-resolution measurement of the thermal diffusivity and its in-plane anisotropy. Although the magnitude of the diffusivity may suggest that it originates from phonons, its anisotropy is comparable with reported values of the electrical resistivity anisotropy. Furthermore, the anisotropy drops sharply below the charge order transition, again similar to the electrical resistivity anisotropy. Both of these observations suggest that the thermal diffusivity has pronounced electronic as well as phononic character. At the same time, the small electrical and thermal conductivities at high temperatures imply that neither well-defined electron nor phonon quasiparticles are present in this material. We interpret our results through a strongly interacting incoherent electron-phonon "soup" picture characterized by a diffusion constant [Formula: see text], where [Formula: see text] is the soup velocity, and scattering of both electrons and phonons saturates a quantum thermal relaxation time [Formula: see text].
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45
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Zhong R, Winn BL, Gu G, Reznik D, Tranquada JM. Evidence for a Nematic Phase in La_{1.75}Sr_{0.25}NiO_{4}. PHYSICAL REVIEW LETTERS 2017; 118:177601. [PMID: 28498689 DOI: 10.1103/physrevlett.118.177601] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Indexed: 06/07/2023]
Abstract
Determining the nature of electronic states in doped Mott insulators remains a challenging task. In the case of tetragonal La_{2-x}Sr_{x}NiO_{4}, the occurrence of diagonal charge and spin stripe order in the ground state is now well established. In contrast, the nature of the high-temperature "disordered" state from which the stripe order develops has long been a subject of controversy, with considerable speculation regarding a polaronic liquid. Following the recent detection of dynamic charge stripes, we use neutron scattering measurements on an x=0.25 crystal to demonstrate that the dispersion of the charge-stripe excitations is anisotropic. This observation provides compelling evidence for the presence of electronic nematic order.
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Affiliation(s)
- Ruidan Zhong
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA
- Materials Science and Engineering Department, Stony Brook University, Stony Brook, New York 11794, USA
| | - Barry L Winn
- Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Genda Gu
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - Dmitry Reznik
- Department of Physics, University of Colorado, Boulder, Colorado 80304, USA
| | - J M Tranquada
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA
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46
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Superconductivity and non-Fermi liquid behavior near a nematic quantum critical point. Proc Natl Acad Sci U S A 2017; 114:4905-4910. [PMID: 28439023 DOI: 10.1073/pnas.1620651114] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Using determinantal quantum Monte Carlo, we compute the properties of a lattice model with spin [Formula: see text] itinerant electrons tuned through a quantum phase transition to an Ising nematic phase. The nematic fluctuations induce superconductivity with a broad dome in the superconducting [Formula: see text] enclosing the nematic quantum critical point. For temperatures above [Formula: see text], we see strikingly non-Fermi liquid behavior, including a "nodal-antinodal dichotomy" reminiscent of that seen in several transition metal oxides. In addition, the critical fluctuations have a strong effect on the low-frequency optical conductivity, resulting in behavior consistent with "bad metal" phenomenology.
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47
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Sato Y, Kawasugi Y, Suda M, Yamamoto HM, Kato R. Critical Behavior in Doping-Driven Metal-Insulator Transition on Single-Crystalline Organic Mott-FET. NANO LETTERS 2017; 17:708-714. [PMID: 28038313 DOI: 10.1021/acs.nanolett.6b03817] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We present the carrier transport properties in the vicinity of a doping-driven Mott transition observed at a field-effect transistor (FET) channel using a single crystal of the typical two-dimensional organic Mott insulator κ-(BEDT-TTF)2CuN(CN)2Cl (κ-Cl). The FET shows a continuous metal-insulator transition (MIT) as electrostatic doping proceeds. The phase transition appears to involve two-step crossovers, one in Hall measurement and the other in conductivity measurement. The crossover in conductivity occurs around the conductance quantum e2/h, and hence is not associated with "bad metal" behavior, which is in stark contrast to the MIT in half-filled organic Mott insulators or that in doped inorganic Mott insulators. Through in-depth scaling analysis of the conductivity, it is found that the above carrier transport properties in the vicinity of the MIT can be described by a high-temperature Mott quantum critical crossover, which is theoretically argued to be a ubiquitous feature of various types of Mott transitions.
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Affiliation(s)
| | | | - Masayuki Suda
- RIKEN, Hirosawa, Wako, Saitama 351-0198, Japan
- Research Center for Integrative Molecular System (CIMoS), Institute for Molecular Science , 38 Nishigo-naka, Myodaiji, Okazaki 444-8585, Japan
| | - Hiroshi M Yamamoto
- RIKEN, Hirosawa, Wako, Saitama 351-0198, Japan
- Research Center for Integrative Molecular System (CIMoS), Institute for Molecular Science , 38 Nishigo-naka, Myodaiji, Okazaki 444-8585, Japan
| | - Reizo Kato
- RIKEN, Hirosawa, Wako, Saitama 351-0198, Japan
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48
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Lee S, Hippalgaonkar K, Yang F, Hong J, Ko C, Suh J, Liu K, Wang K, Urban JJ, Zhang X, Dames C, Hartnoll SA, Delaire O, Wu J. Anomalously low electronic thermal conductivity in metallic vanadium dioxide. Science 2017; 355:371-374. [DOI: 10.1126/science.aag0410] [Citation(s) in RCA: 230] [Impact Index Per Article: 32.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Accepted: 12/22/2016] [Indexed: 01/18/2023]
Affiliation(s)
- Sangwook Lee
- Department of Materials Science and Engineering, University of California, Berkeley, CA 94720, USA
- School of Materials Science and Engineering, Kyungpook National University, Daegu 41566, South Korea
| | - Kedar Hippalgaonkar
- Department of Mechanical Engineering, University of California, Berkeley, CA 94720, USA
- Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research), 2 Fusionopolis Way, Innovis, 08-03, 138634 Singapore
| | - Fan Yang
- Department of Mechanical Engineering, University of California, Berkeley, CA 94720, USA
- The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Jiawang Hong
- School of Aerospace Engineering and Institute of Advanced Structure Technology, Beijing Institute of Technology, Beijing 100081, China
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Changhyun Ko
- Department of Materials Science and Engineering, University of California, Berkeley, CA 94720, USA
| | - Joonki Suh
- Department of Materials Science and Engineering, University of California, Berkeley, CA 94720, USA
| | - Kai Liu
- Department of Materials Science and Engineering, University of California, Berkeley, CA 94720, USA
- Materials Sciences Division, LBNL, Berkeley, CA 94720, USA
| | - Kevin Wang
- Department of Materials Science and Engineering, University of California, Berkeley, CA 94720, USA
| | - Jeffrey J. Urban
- The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Xiang Zhang
- Department of Mechanical Engineering, University of California, Berkeley, CA 94720, USA
- Materials Sciences Division, LBNL, Berkeley, CA 94720, USA
- Department of Physics, King Abdulaziz University, Jeddah 21589, Saudi Arabia
| | - Chris Dames
- Department of Mechanical Engineering, University of California, Berkeley, CA 94720, USA
- Materials Sciences Division, LBNL, Berkeley, CA 94720, USA
| | - Sean A. Hartnoll
- Department of Physics, Stanford University, Stanford, CA 94305, USA
| | - Olivier Delaire
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC 27708, USA
| | - Junqiao Wu
- Department of Materials Science and Engineering, University of California, Berkeley, CA 94720, USA
- Materials Sciences Division, LBNL, Berkeley, CA 94720, USA
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49
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Keumo Tsiaze RM, Wirngo AV, Mkam Tchouobiap SE, Fotue AJ, Baloïtcha E, Hounkonnou MN. Effects of critical fluctuations and dimensionality on the jump in specific heat at the superconducting transition temperature: Application to YBa_{2}Cu_{3}O_{7-δ},Bi_{2}Sr_{2}CaCu_{2}O_{8+δ}, and KOs_{2}O_{6} compounds. Phys Rev E 2016; 93:062105. [PMID: 27415206 DOI: 10.1103/physreve.93.062105] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2015] [Indexed: 11/07/2022]
Abstract
We report on a study of the superconducting order parameter thermodynamic fluctuations in YBa_{2}Cu_{3}O_{7-δ},Bi_{2}Sr_{2}CaCu_{2}O_{8+δ}, and KOs_{2}O_{6} compounds. A nonperturbative technique within the framework of the renormalized Gaussian approach is proposed. The essential features are reported (analytically and numerically) through Ginzburg-Landau (GL) model-based calculations which take into account both the dimension and the microscopic parameters of the system. By presenting a self-consistent approach improvement on the GL theory, a technique for obtaining corrections to the asymptotic critical behavior in terms of nonuniversal parameters is developed. Therefore, corrections to the specific heat and the critical transition temperature for one-, two-, and three-dimensional samples are found taking into account the fact that fluctuations occur at all length scales as the critical point of a system is approached. The GL model in the free-field approximation and the 3D-XY model are suitable for describing the weak and strong fluctuation regimes respectively. However, with a modified quadratic coefficient, the renormalized GL model is able to explain certain experimental observations including the specific heat of complicated systems, such as the cup-rate superconductors and the β-pyrochlore oxides. It is clearly shown that the enhancement, suppression, or rounding of the specific heat jump of high-T_{c} cup-rate superconductors at the transition are indicative of the order parameter thermodynamic fluctuations according to the dimension and the nature of interactions.
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Affiliation(s)
- R M Keumo Tsiaze
- Laboratory of Mechanics, Materials and Structures, Department of Physics, Faculty of Science, University of Yaoundé I, P.O. Box 812, Yaounde, Cameroon.,International Chair in Mathematical Physics and Applications (ICMPA-UNESCO Chair), University of Abomey-Calavi, 072 B.P. 50, Cotonou, Republic of Benin
| | - A V Wirngo
- International Chair in Mathematical Physics and Applications (ICMPA-UNESCO Chair), University of Abomey-Calavi, 072 B.P. 50, Cotonou, Republic of Benin
| | - S E Mkam Tchouobiap
- International Chair in Mathematical Physics and Applications (ICMPA-UNESCO Chair), University of Abomey-Calavi, 072 B.P. 50, Cotonou, Republic of Benin.,Laboratory of Research on Advanced Materials and Nonlinear Science (LaRAMaNS), Department of Physics, Faculty of Science, University of Buea, P.O. Box 63, Buea, Cameroon
| | - A J Fotue
- Laboratory of Mechanics, Materials and Structures, Department of Physics, Faculty of Science, University of Yaoundé I, P.O. Box 812, Yaounde, Cameroon.,Mesoscopic and Multilayer Structure Laboratory, Department of Physics, Faculty of Science, University of Dschang, P.O. Box 479, Dschang, Cameroon
| | - E Baloïtcha
- International Chair in Mathematical Physics and Applications (ICMPA-UNESCO Chair), University of Abomey-Calavi, 072 B.P. 50, Cotonou, Republic of Benin
| | - M N Hounkonnou
- International Chair in Mathematical Physics and Applications (ICMPA-UNESCO Chair), University of Abomey-Calavi, 072 B.P. 50, Cotonou, Republic of Benin
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50
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Deng X, Haule K, Kotliar G. Transport Properties of Metallic Ruthenates: A DFT+DMFT Investigation. PHYSICAL REVIEW LETTERS 2016; 116:256401. [PMID: 27391734 DOI: 10.1103/physrevlett.116.256401] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Indexed: 06/06/2023]
Abstract
We present a systematical theoretical study on the transport properties of an archetypal family of Hund's metals, Sr_{2}RuO_{4}, Sr_{3}Ru_{2}O_{7}, SrRuO_{3}, and CaRuO_{3}, within the combination of first principles density functional theory and dynamical mean field theory. The agreement between theory and experiments for optical conductivity and resistivity is good, which indicates that electron-electron scattering dominates the transport of ruthenates. We demonstrate that in the single-site dynamical mean field approach the transport properties of Hund's metals fall into the scenario of "resilient quasiparticles." We explain why the single layered compound Sr_{2}RuO_{4} has a relative weak correlation with respect to its siblings, which corroborates its good metallicity.
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Affiliation(s)
- Xiaoyu Deng
- Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA
| | - Kristjan Haule
- Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA
| | - Gabriel Kotliar
- Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA
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