1
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Rammal H, Ralko A, Ciuchi S, Fratini S. Transient Localization from the Interaction with Quantum Bosons. PHYSICAL REVIEW LETTERS 2024; 132:266502. [PMID: 38996285 DOI: 10.1103/physrevlett.132.266502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Accepted: 05/22/2024] [Indexed: 07/14/2024]
Abstract
We carefully revisit the electron-boson scattering problem, going beyond weak-coupling expansions and popular semiclassical treatments. By providing numerically exact results valid at finite temperatures, we demonstrate the existence of a broad regime of electron-boson scattering where quantum localization processes become relevant despite the absence of extrinsic disorder. Localization in the Anderson sense is caused by the dynamical randomness resulting from a large thermal boson population, being, however, effective only at transient times before diffusion can set in. Compelling evidence of this transient localization phenomenon is provided by the observation of a distinctive displaced Drude peak in the optical absorption and the ensuing suppression of conductivity. Our findings identify a general route for anomalous metallic behavior that can broadly apply in interacting quantum matter.
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2
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Brar J, Pathak S, Khalid S, Rawat R, Singh RS, Bindu R. Structural and physical properties of Ni1-xV xalloys around and away from quantum critical point. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2024; 36:195401. [PMID: 38306701 DOI: 10.1088/1361-648x/ad258d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Accepted: 02/02/2024] [Indexed: 02/04/2024]
Abstract
We investigate the room temperature structure (global and local), temperature dependent magnetic and transport behaviour of Ni1-xVx(0⩽x⩽0.13) alloys. Our Energy Dispersive Analysis of x-rays results show that the prepared compositions are stoichiometric. With increase in V doping, the compounds exhibit a quantum phase transition aroundxc= 0.12, where the ferromagnetic phase is suppressed. Our results show that all the compounds stabilize in face centred cubic structure at RT and the lattice parameter shows unusual behaviour close toxc. The magnetic and heat capacity studies show signature of Griffiths phase on either side ofxc. From 25 K to the lowest collected temperature, we observe a linear T dependence of resistivity atx = 0.1 and aroundxc, which is separated by a Fermi-liquid region aroundx = 0.106. This suggests that the origin of the transport behaviour is different around the quantum critical point and away from it. Our Ni K-edge x-ray Absorption Spectroscopy results show that there is a significant reduction in the first coordination number around Ni central atom on doping. Further, with doping, there is distortion in the first coordination shell around Ni. This suggests, with V doping, the local structure around Ni is different from the global structure as obtained from the x-ray Diffraction results. Interestingly, with doping, we observe a direct connection between the extent of distortion at RT and the magnetic disorder obtained at 2 K. We believe our results will motivate the scientific community to further study the interplay between the structural disorder and quantum fluctuations with temperature at the local level.
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Affiliation(s)
- Jaskirat Brar
- School of Physical Sciences, Indian Institute of Technology Mandi, Kamand, Himachal Pradesh 175005, India
| | - Swati Pathak
- School of Physical Sciences, Indian Institute of Technology Mandi, Kamand, Himachal Pradesh 175005, India
| | - S Khalid
- National Synchrotron Light Source, Brookhaven National Laboratory, Upton, NY 11973, United States of America
| | - R Rawat
- UGC DAE Consortium for Scientific Research, University Campus, Khandwa Road, Indore 452017, India
| | - R S Singh
- Indian Institute of Science Education and Research, Bhopal, M.P. 462023, India
| | - R Bindu
- School of Physical Sciences, Indian Institute of Technology Mandi, Kamand, Himachal Pradesh 175005, India
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3
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Wang Z, Liu Y, Ji C, Wang J. Quantum phase transitions in two-dimensional superconductors: a review on recent experimental progress. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2023; 87:014502. [PMID: 38086096 DOI: 10.1088/1361-6633/ad14f3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Accepted: 12/12/2023] [Indexed: 12/30/2023]
Abstract
Superconductor-insulator/metal transition (SMT) as a paradigm of quantum phase transition has been a research highlight over the last three decades. Benefit from recent developments in the fabrication and measurements of two-dimensional (2D) superconducting films and nanodevices, unprecedented quantum phenomena have been revealed in the quantum phase transitions of 2D superconductors. In this review, we introduce the recent progress on quantum phase transitions in 2D superconductors, focusing on the quantum Griffiths singularity (QGS) and anomalous metal state. Characterized by a divergent critical exponent when approaching zero temperature, QGS of SMT is discovered in ultrathin crystalline Ga films and subsequently detected in various 2D superconductors. The universality of QGS indicates the profound influence of quenched disorder on quantum phase transitions. Besides, in a 2D superconducting system, whether a metallic ground state can exist is a long-sought mystery. Early experimental studies indicate an intermediate metallic state in the quantum phase transition of 2D superconductors. Recently, in high-temperature superconducting films with patterned nanopores, a robust anomalous metal state (i.e. quantum metal or Bose metal) has been detected, featured as the saturated resistance in the low temperature regime. Moreover, the charge-2equantum oscillations are observed in nanopatterned films, indicating the bosonic nature of the anomalous metal state and ending the debate on whether bosons can exist as a metal. The evidences of the anomalous metal states have also been reported in crystalline epitaxial thin films and exfoliated nanoflakes, as well as granular composite films. High quality filters are used in these works to exclude the influence of external high frequency noises in ultralow temperature measurements. The observations of QGS and metallic ground states in 2D superconductors not only reveal the prominent role of quantum fluctuations and dissipations but also provide new perspective to explore quantum phase transitions in superconducting systems.
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Affiliation(s)
- Ziqiao Wang
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, People's Republic of China
| | - Yi Liu
- Department of Physics and Beijing Key Laboratory of Opto-electronic Functional Materials & Micro-nano Devices, Renmin University of China, Beijing 100872, People's Republic of China
- Key Laboratory of Quantum State Construction and Manipulation (Ministry of Education), Renmin University of China, Beijing 100872, People's Republic of China
| | - Chengcheng Ji
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, People's Republic of China
- Hefei National Laboratory, Hefei 230088, People's Republic of China
| | - Jian Wang
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, People's Republic of China
- Collaborative Innovation Center of Quantum Matter, Beijing 100871, People's Republic of China
- Hefei National Laboratory, Hefei 230088, People's Republic of China
- CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, People's Republic of China
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4
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Luo W, Akbarzadeh A, Nahas Y, Prokhorenko S, Bellaiche L. Quantum criticality at cryogenic melting of polar bubble lattices. Nat Commun 2023; 14:7874. [PMID: 38036499 PMCID: PMC10689468 DOI: 10.1038/s41467-023-43598-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Accepted: 11/13/2023] [Indexed: 12/02/2023] Open
Abstract
Quantum fluctuations (QFs) caused by zero-point phonon vibrations (ZPPVs) are known to prevent the occurrence of polar phases in bulk incipient ferroelectrics down to 0 K. On the other hand, little is known about the effects of QFs on the recently discovered topological patterns in ferroelectric nanostructures. Here, by using an atomistic effective Hamiltonian within classical Monte Carlo (CMC) and path integral quantum Monte Carlo (PI-QMC), we unveil how QFs affect the topology of several dipolar phases in ultrathin Pb(Zr0.4Ti0.6)O3 (PZT) films. In particular, our PI-QMC simulations show that the ZPPVs do not suppress polar patterns but rather stabilize the labyrinth, bimeron and bubble phases within a wider range of bias field magnitudes. Moreover, we reveal that quantum fluctuations induce a quantum critical point (QCP) separating a hexagonal bubble lattice from a liquid-like state characterized by spontaneous motion, creation and annihilation of polar bubbles at cryogenic temperatures. Finally, we show that the discovered quantum melting is associated with anomalous physical response, as, e.g., demonstrated by a negative longitudinal piezoelectric coefficient.
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Affiliation(s)
- Wei Luo
- Physics Department and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, AR, 72701, USA
| | - Alireza Akbarzadeh
- Physics Department and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, AR, 72701, USA
- Science, Engineering, and Geosciences, Lonestar College, 9191 Barker Cypress Road, Cypress, TX, 77433, USA
| | - Yousra Nahas
- Physics Department and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, AR, 72701, USA
| | - Sergei Prokhorenko
- Physics Department and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, AR, 72701, USA.
| | - Laurent Bellaiche
- Physics Department and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, AR, 72701, USA.
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5
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Chen L, Lowder DT, Bakali E, Andrews AM, Schrenk W, Waas M, Svagera R, Eguchi G, Prochaska L, Wang Y, Setty C, Sur S, Si Q, Paschen S, Natelson D. Shot noise in a strange metal. Science 2023; 382:907-911. [PMID: 37995251 DOI: 10.1126/science.abq6100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Accepted: 10/12/2023] [Indexed: 11/25/2023]
Abstract
Strange-metal behavior has been observed in materials ranging from high-temperature superconductors to heavy fermion metals. In conventional metals, current is carried by quasiparticles; although it has been suggested that quasiparticles are absent in strange metals, direct experimental evidence is lacking. We measured shot noise to probe the granularity of the current-carrying excitations in nanowires of the heavy fermion strange metal YbRh2Si2. When compared with conventional metals, shot noise in these nanowires is strongly suppressed. This suppression cannot be attributed to either electron-phonon or electron-electron interactions in a Fermi liquid, which suggests that the current is not carried by well-defined quasiparticles in the strange-metal regime that we probed. Our work sets the stage for similar studies of other strange metals.
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Affiliation(s)
- Liyang Chen
- Applied Physics Graduate Program, Rice University, TX 77005, USA
| | - Dale T Lowder
- Department of Physics and Astronomy, Rice Center for Quantum Materials, Rice University, Houston, TX 77005, USA
| | - Emine Bakali
- Institute of Solid State Physics, TU Wien, Wiedner Hauptstraße 8-10, 1040 Vienna, Austria
| | - Aaron Maxwell Andrews
- Institute of Solid State Electronics, TU Wien, Gußhausstraße 25-25a, Gebäude CH, 1040 Vienna, Austria
| | - Werner Schrenk
- Center for Micro and Nanostructures, TU Wien, Gußhausstraße 25-25a, Gebäude CH, 1040 Vienna, Austria
| | - Monika Waas
- Institute of Solid State Physics, TU Wien, Wiedner Hauptstraße 8-10, 1040 Vienna, Austria
| | - Robert Svagera
- Institute of Solid State Physics, TU Wien, Wiedner Hauptstraße 8-10, 1040 Vienna, Austria
| | - Gaku Eguchi
- Institute of Solid State Physics, TU Wien, Wiedner Hauptstraße 8-10, 1040 Vienna, Austria
| | - Lukas Prochaska
- Institute of Solid State Physics, TU Wien, Wiedner Hauptstraße 8-10, 1040 Vienna, Austria
| | - Yiming Wang
- Department of Physics and Astronomy, Rice Center for Quantum Materials, Rice University, Houston, TX 77005, USA
| | - Chandan Setty
- Department of Physics and Astronomy, Rice Center for Quantum Materials, Rice University, Houston, TX 77005, USA
| | - Shouvik Sur
- Department of Physics and Astronomy, Rice Center for Quantum Materials, Rice University, Houston, TX 77005, USA
| | - Qimiao Si
- Department of Physics and Astronomy, Rice Center for Quantum Materials, Rice University, Houston, TX 77005, USA
| | - Silke Paschen
- Institute of Solid State Physics, TU Wien, Wiedner Hauptstraße 8-10, 1040 Vienna, Austria
| | - Douglas Natelson
- Department of Physics and Astronomy, Rice Center for Quantum Materials, Rice University, Houston, TX 77005, USA
- Department of Electrical and Computer Engineering, Rice University, Houston, TX 77005, USA
- Department of Materials Science and NanoEngineering, Rice University, Houston, TX 77005, USA
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6
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Wang H, Park TB, Kim J, Jang H, Bauer ED, Thompson JD, Park T. Evidence for charge delocalization crossover in the quantum critical superconductor CeRhIn 5. Nat Commun 2023; 14:7341. [PMID: 37957188 PMCID: PMC10643617 DOI: 10.1038/s41467-023-42965-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 10/25/2023] [Indexed: 11/15/2023] Open
Abstract
The nature of charge degrees-of-freedom distinguishes scenarios for interpreting the character of a second order magnetic transition at zero temperature, that is, a magnetic quantum critical point (QCP). Heavy-fermion systems are prototypes of this paradigm, and in those, the relevant question is where, relative to a magnetic QCP, does the Kondo effect delocalize their f-electron degrees-of-freedom. Herein, we use pressure-dependent Hall measurements to identify a finite-temperature scale Eloc that signals a crossover from f-localized to f-delocalized character. As a function of pressure, Eloc(P) extrapolates smoothly to zero temperature at the antiferromagnetic QCP of CeRhIn5 where its Fermi surface reconstructs, hallmarks of Kondo-breakdown criticality that generates critical magnetic and charge fluctuations. In 4.4% Sn-doped CeRhIn5, however, Eloc(P) extrapolates into its magnetically ordered phase and is decoupled from the pressure-induced magnetic QCP, which implies a spin-density-wave (SDW) type of criticality that produces only critical fluctuations of the SDW order parameter. Our results demonstrate the importance of experimentally determining Eloc to characterize quantum criticality and the associated consequences for understanding the pairing mechanism of superconductivity that reaches a maximum Tc in both materials at their respective magnetic QCP.
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Affiliation(s)
- Honghong Wang
- Center for Quantum Materials and Superconductivity (CQMS), Sungkyunkwan University, Suwon, South Korea
- Department of Physics, Sungkyunkwan University, Suwon, South Korea
| | - Tae Beom Park
- Center for Quantum Materials and Superconductivity (CQMS), Sungkyunkwan University, Suwon, South Korea
- Department of Physics, Sungkyunkwan University, Suwon, South Korea
- Institute of Basic Science, Sungkyunkwan University, Suwon, South Korea
| | - Jihyun Kim
- Center for Quantum Materials and Superconductivity (CQMS), Sungkyunkwan University, Suwon, South Korea
- Department of Physics, Sungkyunkwan University, Suwon, South Korea
| | - Harim Jang
- Center for Quantum Materials and Superconductivity (CQMS), Sungkyunkwan University, Suwon, South Korea
- Department of Physics, Sungkyunkwan University, Suwon, South Korea
| | - Eric D Bauer
- Los Alamos National Laboratory, Los Alamos, NM, USA
| | | | - Tuson Park
- Center for Quantum Materials and Superconductivity (CQMS), Sungkyunkwan University, Suwon, South Korea.
- Department of Physics, Sungkyunkwan University, Suwon, South Korea.
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7
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Lake E, Senthil T. Non-Fermi Liquids from Kinetic Constraints in Tilted Optical Lattices. PHYSICAL REVIEW LETTERS 2023; 131:043403. [PMID: 37566868 DOI: 10.1103/physrevlett.131.043403] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Accepted: 07/03/2023] [Indexed: 08/13/2023]
Abstract
We study Fermi-Hubbard models with kinetically constrained dynamics that conserves both total particle number and total center of mass, a situation that arises when interacting fermions are placed in strongly tilted optical lattices. Through a combination of analytics and numerics, we show how the kinetic constraints stabilize an exotic non-Fermi liquid phase described by fermions coupled to a gapless bosonic field, which in several respects mimics a dynamical gauge field. This offers a novel route towards the study of non-Fermi liquid phases in the precision environments afforded by ultracold atom platforms.
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Affiliation(s)
- Ethan Lake
- Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - T Senthil
- Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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8
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Lunts P, Albergo MS, Lindsey M. Non-Hertz-Millis scaling of the antiferromagnetic quantum critical metal via scalable Hybrid Monte Carlo. Nat Commun 2023; 14:2547. [PMID: 37137882 PMCID: PMC10156689 DOI: 10.1038/s41467-023-37686-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 03/23/2023] [Indexed: 05/05/2023] Open
Abstract
A key component of the phase diagram of many iron-based superconductors and electron-doped cuprates is believed to be a quantum critical point (QCP), delineating the onset of antiferromagnetic spin-density wave order in a quasi-two-dimensional metal. The universality class of this QCP is believed to play a fundamental role in the description of the proximate non-Fermi liquid behavior and superconducting phase. A minimal model for this transition is the O(3) spin-fermion model. Despite many efforts, a definitive characterization of its universal properties is still lacking. Here, we numerically study the O(3) spin-fermion model and extract the scaling exponents and functional form of the static and zero-momentum dynamical spin susceptibility. We do this using a Hybrid Monte Carlo (HMC) algorithm with a novel auto-tuning procedure, which allows us to study unprecedentedly large systems of 80 × 80 sites. We find a strong violation of the Hertz-Millis form, contrary to all previous numerical results. Furthermore, the form that we do observe provides good evidence that the universal scaling is actually governed by the analytically tractable fixed point discovered near perfect "hot-spot'" nesting, even for a larger nesting window. Our predictions can be directly tested with neutron scattering. Additionally, the HMC method we introduce is generic and can be used to study other fermionic models of quantum criticality, where there is a strong need to simulate large systems.
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Affiliation(s)
- Peter Lunts
- Joint Quantum Institute and Department of Physics, University of Maryland, College Park, MD, 20742, USA.
- Center for Computational Quantum Physics, Flatiron Institute, 162 5th Avenue, New York, NY, 10010, USA.
| | - Michael S Albergo
- Center for Cosmology and Particle Physics, New York University, New York, NY, 10003, USA
| | - Michael Lindsey
- Courant Institute of Mathematical Sciences, New York University, New York, NY, 10012, USA
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9
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Dissipative Quantum Criticality as a Source of Strange Metal Behavior. Symmetry (Basel) 2023. [DOI: 10.3390/sym15030569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023] Open
Abstract
The strange metal behavior, usually characterized by a linear-in-temperature (T) resistivity, is a still unsolved mystery in solid-state physics. It is often associated with the proximity to a quantum critical point (a second order transition at temperature T=0, leading to a broken symmetry phase) focusing on the related divergent order parameter correlation length. Here, we propose a paradigmatic shift, focusing on a divergent characteristic time scale due to a divergent dissipation acting on the fluctuating critical modes while their correlation length stays finite. To achieve a divergent dissipation, we propose a mechanism based on the coupling between a local order parameter fluctuation and electron density diffusive modes that accounts both for the linear-in-T resistivity and for the logarithmic specific heat versus temperature ratio CV/T∼log(1/T), down to low temperatures.
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10
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Chang YY, Lei H, Petrovic C, Chung CH. The scaled-invariant Planckian metal and quantum criticality in Ce 1-xNd xCoIn 5. Nat Commun 2023; 14:581. [PMID: 36737608 PMCID: PMC9898561 DOI: 10.1038/s41467-023-36194-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 01/17/2023] [Indexed: 02/05/2023] Open
Abstract
The mysterious Planckian metal state, showing perfect T-linear resistivity associated with universal scattering rate, 1/τ = αkBT/ℏ with α ~ 1, has been observed in the normal state of various strongly correlated superconductors close to a quantum critical point. However, its microscopic origin and link to quantum criticality remains an outstanding open problem. Here, we observe quantum-critical T/B-scaling of the Planckian metal state in resistivity and heat capacity of heavy-electron superconductor Ce1-xNdxCoIn5 in magnetic fields near the edge of antiferromagnetism at the critical doping xc ~ 0.03. We present clear experimental evidences of Kondo hybridization being quantum critical at xc. We provide a generic microscopic mechanism to qualitatively account for this quantum critical Planckian state within the quasi-two dimensional Kondo-Heisenberg lattice model near Kondo breakdown transition. We find α is a non-universal constant and depends inversely on the square of Kondo hybridization strength.
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Affiliation(s)
- Yung-Yeh Chang
- grid.468468.00000 0000 9060 5564Physics Division, National Center for Theoretical Sciences, Taipei, 10617 Taiwan Republic of China ,grid.260539.b0000 0001 2059 7017Department of Electrophysics, National Yang-Ming Chiao-Tung University, Hsinchu, 300 Taiwan Republic of China
| | - Hechang Lei
- grid.202665.50000 0001 2188 4229Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, NY 11973-5000 USA ,grid.24539.390000 0004 0368 8103Present Address: Department of Physics and Beijing Key Laboratory of Opto-electronic Functional Materials & Micro-nano Devices, Renmin University of China, Beijing, 100872 People’s Republic of China
| | - C. Petrovic
- grid.202665.50000 0001 2188 4229Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, NY 11973-5000 USA
| | - Chung-Hou Chung
- grid.468468.00000 0000 9060 5564Physics Division, National Center for Theoretical Sciences, Taipei, 10617 Taiwan Republic of China ,grid.260539.b0000 0001 2059 7017Department of Electrophysics, National Yang-Ming Chiao-Tung University, Hsinchu, 300 Taiwan Republic of China
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11
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Yang YF. An emerging global picture of heavy fermion physics. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 35:103002. [PMID: 36542859 DOI: 10.1088/1361-648x/acadc4] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Accepted: 12/21/2022] [Indexed: 06/17/2023]
Abstract
Recent progresses using state-of-the-art experimental techniques have motivated a number of new insights on heavy fermion physics. This article gives a brief summary of the author's research along this direction. We discuss five major topics including: (1) development of phase coherence and two-stage hybridization; (2) two-fluid behavior and hidden universal scaling; (3) quantum phase transitions and fractionalized heavy fermion liquid; (4) quantum critical superconductivity; (5) material-specific properties. These cover the most essential parts of heavy fermion physics and lead to an emerging global picture beyond conventional theories based on mean-field or local approximations.
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Affiliation(s)
- Yi-Feng Yang
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, People's Republic of China
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12
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Haraguchi Y, Katori HA. Honeycomb lattice iridate on the verge of Mott-collapse. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 34:465602. [PMID: 36096090 DOI: 10.1088/1361-648x/ac916e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2022] [Accepted: 09/12/2022] [Indexed: 06/15/2023]
Abstract
A new honeycomb lattice iridate (La,Na)IrO3(≈LaNaIr2O6) is successfully synthesized from the spin-orbit coupled Mott insulator Na2IrO3by replacing the interlayer Na+ions with La3+ions. (La,Na)IrO3shows a finite Sommerfeld term in heat capacity and a -lnTdependence of resistivity, indicating a realization of a metallic state driven by a Mott collapse. Furthermore, crystal structure analysis reveals the formation of Ir zig-zag chains with metal-metal bonding, increasing kinetic energy resulting in the Mott collapse. This observation would be due to a Mott collapse induced in aJeff= 1/2 spin-orbit coupling Mott insulator with an Ir honeycomb lattice by topochemical control of the ionic configuration.
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Affiliation(s)
- Yuya Haraguchi
- Department of Applied Physics and Chemical Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588, Japan
| | - Hiroko Aruga Katori
- Department of Applied Physics and Chemical Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588, Japan
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13
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Emergence of mesoscale quantum phase transitions in a ferromagnet. Nature 2022; 609:65-70. [PMID: 36045242 DOI: 10.1038/s41586-022-04995-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Accepted: 06/17/2022] [Indexed: 11/08/2022]
Abstract
Mesoscale patterns as observed in, for example, ferromagnets, ferroelectrics, superconductors, monomolecular films or block copolymers1,2 reflect spatial variations of a pertinent order parameter at length scales and time scales that may be described classically. This raises the question for the relevance of mesoscale patterns near zero-temperature phase transitions, also known as quantum phase transitions. Here we report the magnetic susceptibility of LiHoF4-a dipolar Ising ferromagnet-near a well-understood transverse-field quantum critical point (TF-QCP)3,4. When tilting the magnetic field away from the hard axis such that the Ising symmetry is always broken, a line of well-defined phase transitions emerges from the TF-QCP, characteristic of further symmetry breaking, in stark contrast to a crossover expected microscopically. We show that the scenario of a continuous suppression of ferromagnetic domains, representing a breaking of translation symmetry on mesoscopic scales in an environment of broken magnetic Ising symmetry on microscopic scales, is in excellent qualitative and quantitative agreement with the field and temperature dependence of the susceptibility and the magnetic phase diagram of LiHoF4 under tilted field. This identifies a new type of phase transition that may be referred to as mesoscale quantum criticality, which emanates from the textbook example of a microscopic ferromagnetic TF-QCP. Our results establish the surroundings of quantum phase transitions as a regime of mesoscale pattern formation, in which non-analytical quantum dynamics and materials properties without classical analogue may be expected.
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14
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Weber M, Luitz DJ, Assaad FF. Dissipation-Induced Order: The S=1/2 Quantum Spin Chain Coupled to an Ohmic Bath. PHYSICAL REVIEW LETTERS 2022; 129:056402. [PMID: 35960576 DOI: 10.1103/physrevlett.129.056402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 07/04/2022] [Indexed: 06/15/2023]
Abstract
We consider an S=1/2 antiferromagnetic quantum Heisenberg chain where each site is coupled to an independent bosonic bath with ohmic dissipation. The coupling to the bath preserves the global SO(3) spin symmetry. Using large-scale, approximation-free quantum Monte Carlo simulations, we show that any finite coupling to the bath suffices to stabilize long-range antiferromagnetic order. This is in stark contrast to the isolated Heisenberg chain where spontaneous breaking of the SO(3) symmetry is forbidden by the Mermin-Wagner theorem. A linear spin-wave theory analysis confirms that the memory of the bath and the concomitant retarded interaction stabilize the order. For the Heisenberg chain, the ohmic bath is a marginal perturbation so that exponentially large system sizes are required to observe long-range order at small couplings. Below this length scale, our numerics is dominated by a crossover regime where spin correlations show different power-law behaviors in space and time. We discuss the experimental relevance of this crossover phenomena.
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Affiliation(s)
- Manuel Weber
- Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Str. 38, 01187 Dresden, Germany
| | - David J Luitz
- Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Str. 38, 01187 Dresden, Germany
- Physikalisches Institut, Universität Bonn, Nussallee 12, 53115 Bonn, Germany
| | - Fakher F Assaad
- Institut für Theoretische Physik und Astrophysik, Universität Würzburg, 97074 Würzburg, Germany
- Würzburg-Dresden Cluster of Excellence ct.qmat, Am Hubland, 97074 Würzburg, Germany
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15
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Non-Fermi liquid phase and linear-in-temperature scattering rate in overdoped two-dimensional Hubbard model. Proc Natl Acad Sci U S A 2022; 119:e2115819119. [PMID: 35320041 PMCID: PMC9060486 DOI: 10.1073/pnas.2115819119] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
SignificanceMost metals display an electron-scattering rate [Formula: see text] that follows [Formula: see text] at low temperatures, as prescribed by Fermi liquid theory. But there are important exceptions. One of the most prominent examples is the "strange" metal regime in overdoped cuprate supercondcutors, which exhibits a linear T dependence of the scattering rate [Formula: see text] that reaches a putative Planckian limit. Here, using cutting-edge computational approaches, we show that T-linear scattering rate can emerge from the overdoped Hubbard model at low temperatures. Our results agree with cuprate experiments in various aspects but challenge the Planckian limit. Finally, by identifying antiferromagnetic fluctuations as the physical origin of the T-linear scattering rate, we discover the microscopic mechanism of strange metallicity in cuprates.
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16
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Abstract
Recent resonant X-ray scattering experiments on cuprates allowed to identify a new kind of collective excitations, known as charge density fluctuations, which have finite characteristic wave vector, short correlation length and small characteristic energy. It was then shown that these fluctuations provide a microscopic scattering mechanism that accounts for the anomalous transport properties of cuprates in the so-called strange-metal phase and are a source of anomalies in the specific heat. In this work, we retrace the main steps that led us to attributing a central role to charge density fluctuations in the strange-metal phase of cuprates, discuss the state of the art on the issue and provide an in-depth analysis of the contribution of charge density fluctuations to the specific heat.
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17
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Abstract
The elusive strange metal phase (ground state) was observed in a variety of quantum materials, notably in f-electron–based rare-earth intermetallic compounds. Its emergence has remained unclear. Here, we propose a generic mechanism for this phenomenon driven by the interplay of the gapless fermionic short-ranged antiferromagnetic spin correlation and critical bosonic charge fluctuations near a Kondo breakdown quantum phase transition. It is manifested as a fluctuating Kondo-scattering–stabilized critical (gapless) fermionic spin liquid. It shows ω/T scaling in dynamical electron scattering rate, a signature of quantum criticality. Our results on quasilinear-in-temperature scattering rate and logarithmic-in-temperature divergence in specific heat coefficient as temperature vanishes were recently seen in CePd1−xNixAl. A major mystery in strongly interacting quantum systems is the microscopic origin of the “strange metal” phenomenology, with unconventional metallic behavior that defies Landau’s Fermi liquid framework for ordinary metals. This state is found across a wide range of quantum materials, notably in rare-earth intermetallic compounds at finite temperatures (T) near a magnetic quantum phase transition, and shows a quasilinear-in-temperature resistivity and a logarithmic-in-temperature specific heat coefficient. Recently, an even more enigmatic behavior pointing toward a stable strange metal ground state was observed in CePd1−xNixAl, a geometrically frustrated Kondo lattice compound. Here, we propose a mechanism for such phenomena driven by the interplay of the gapless fermionic short-ranged antiferromagnetic spin correlations (spinons) and critical bosonic charge (holons) fluctuations near a Kondo breakdown quantum phase transition. Within a dynamical large-N approach to the Kondo–Heisenberg lattice model, the strange metal phase is realized in transport and thermodynamical quantities. It is manifested as a fluctuating Kondo-scattering–stabilized critical (gapless) fermionic spin-liquid metal. It shows ω/T scaling in dynamical electron scattering rate, a signature of quantum criticality. Our results offer a qualitative understanding of the CePd1−xNixAl compound and suggest a possibility of realizing the quantum critical strange metal phase in correlated electron systems in general.
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18
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Liu ZH, Vojta M, Assaad FF, Janssen L. Metallic and Deconfined Quantum Criticality in Dirac Systems. PHYSICAL REVIEW LETTERS 2022; 128:087201. [PMID: 35275685 DOI: 10.1103/physrevlett.128.087201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 01/25/2022] [Indexed: 06/14/2023]
Abstract
Motivated by the physics of spin-orbital liquids, we study a model of interacting Dirac fermions on a bilayer honeycomb lattice at half filling, featuring an explicit global SO(3)×U(1) symmetry. Using large-scale auxiliary-field quantum Monte Carlo (QMC) simulations, we locate two zero-temperature phase transitions as function of increasing interaction strength. First, we observe a continuous transition from the weakly interacting semimetal to a different semimetallic phase in which the SO(3) symmetry is spontaneously broken and where two out of three Dirac cones acquire a mass gap. The associated quantum critical point can be understood in terms of a Gross-Neveu-SO(3) theory. Second, we subsequently observe a transition toward an insulating phase in which the SO(3) symmetry is restored and the U(1) symmetry is spontaneously broken. While strongly first order at the mean-field level, the QMC data are consistent with a direct and continuous transition. It is thus a candidate for a new type of deconfined quantum critical point that features gapless fermionic degrees of freedom.
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Affiliation(s)
- Zi Hong Liu
- Institut für Theoretische Physik und Astrophysik and Würzburg-Dresden Cluster of Excellence ct.qmat, Universität Würzburg, 97074 Würzburg, Germany
| | - Matthias Vojta
- Institut für Theoretische Physik and Würzburg-Dresden Cluster of Excellence ct.qmat, Technische Universität Dresden, 01062 Dresden, Germany
| | - Fakher F Assaad
- Institut für Theoretische Physik und Astrophysik and Würzburg-Dresden Cluster of Excellence ct.qmat, Universität Würzburg, 97074 Würzburg, Germany
| | - Lukas Janssen
- Institut für Theoretische Physik and Würzburg-Dresden Cluster of Excellence ct.qmat, Technische Universität Dresden, 01062 Dresden, Germany
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19
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Palmstrom JC, Walmsley P, Straquadine JAW, Sorensen ME, Hannahs ST, Burns DH, Fisher IR. Comparison of temperature and doping dependence of elastoresistivity near a putative nematic quantum critical point. Nat Commun 2022; 13:1011. [PMID: 35197491 PMCID: PMC8866430 DOI: 10.1038/s41467-022-28583-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 01/26/2022] [Indexed: 11/25/2022] Open
Abstract
Strong electronic nematic fluctuations have been discovered near optimal doping for several families of Fe-based superconductors, motivating the search for a possible link between these fluctuations, nematic quantum criticality, and high temperature superconductivity. Here we probe a key prediction of quantum criticality, namely power-law dependence of the associated nematic susceptibility as a function of composition and temperature approaching the compositionally tuned putative quantum critical point. To probe the ‘bare’ quantum critical point requires suppression of the superconducting state, which we achieve by using large magnetic fields, up to 45 T, while performing elastoresistivity measurements to follow the nematic susceptibility. We performed these measurements for the prototypical electron-doped pnictide, Ba(Fe1−xCox)2As2, over a dense comb of dopings. We find that close to the putative quantum critical point, the elastoresistivity appears to obey power-law behavior as a function of composition over almost a decade of variation in composition. Paradoxically, however, we also find that the temperature dependence for compositions close to the critical value cannot be described by a single power law. Evidence for quantum criticality in Fe-based superconductors is still being accumulated. Here, the authors observe power-law behavior of the elastoresistivity as a function of composition in Ba(Fe1−xCox)2As2 near a putative nematic quantum critical point, consistent with expectations for quantum criticality, while the temperature dependence near the critical doping deviates from a power law.
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Affiliation(s)
- J C Palmstrom
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA, 94305, USA. .,Department of Applied Physics, Stanford University, Stanford, CA, 94305, USA. .,Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA. .,National High Magnetic Field Laboratory, Los Alamos, NM, 97545, USA.
| | - P Walmsley
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA, 94305, USA.,Department of Applied Physics, Stanford University, Stanford, CA, 94305, USA.,Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA
| | - J A W Straquadine
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA, 94305, USA.,Department of Applied Physics, Stanford University, Stanford, CA, 94305, USA.,Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA
| | - M E Sorensen
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA, 94305, USA.,Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA.,Department of Physics, Stanford University, Stanford, CA, 94305, USA
| | - S T Hannahs
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL, 32310, USA
| | - D H Burns
- Department of Geological Sciences, Stanford University, Stanford, CA, 94305, USA
| | - I R Fisher
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA, 94305, USA. .,Department of Applied Physics, Stanford University, Stanford, CA, 94305, USA. .,Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA.
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20
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Meng F, Ge M, Wei W, Rahman A, Liu W, Wang A, Zhao J, Fan J, Ma C, Pi L, Zhang L, Zhang Y. Tricritical-point phase diagram in PrCu 9Sn 4. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 34:155803. [PMID: 35086086 DOI: 10.1088/1361-648x/ac4f7c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 01/27/2022] [Indexed: 06/14/2023]
Abstract
Tricritical phenomenon appearing in multiple phases is a fundamental and attractive issue in condensed-matter physics. In this work, a field-modulated tricritical phenomenon is realized in single-crystal PrCu9Sn4. The magnetization under variable directions of field indicates strong magnetic anisotropy in PrCu9Sn4, which reveals ferromagnetic coupling forH//c. A paramagnetic-to-ferromagnetic magnetic transition occurs withH//catTC= 11.7 K, which is evidenced to be of a first-ordered type. The systematical study of the critical behavior gives thatβ= 0.195(8),γ= 0.911(1), andδ= 0.0592(1) forH//cconsistent with a tricritical mean-field model, which suggests a field-modulated tricritical phenomenon. A detailedH-Tphase diagram around the tricritical point (TCP) is constructed for single-crystal PrCu9Sn4forH//c, where ferromagnetic state, forced ferromagnetic phase and paramagnetic state meet at the TCP (Htr= 799 kOe,Ttr= 11.3 K). The single-crystal PrCu9Sn4supplies a platform to deep investigate the field-modulated magnetic couplings and tricritical phenomenon.
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Affiliation(s)
- Fanying Meng
- Anhui Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, People's Republic of China
- Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, People's Republic of China
- The High Magnetic Field Laboratory of Anhui Province, Hefei 230031, People's Republic of China
| | - Min Ge
- Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, People's Republic of China
| | - Wensen Wei
- Anhui Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, People's Republic of China
- The High Magnetic Field Laboratory of Anhui Province, Hefei 230031, People's Republic of China
| | - Azizur Rahman
- Anhui Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, People's Republic of China
- Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, People's Republic of China
| | - Wei Liu
- Institutes of Physical Science and Information Technology, Anhui University, Hefei, 230601, People's Republic of China
| | - Aina Wang
- Anhui Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, People's Republic of China
- Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, People's Republic of China
- The High Magnetic Field Laboratory of Anhui Province, Hefei 230031, People's Republic of China
| | - Jun Zhao
- Anhui Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, People's Republic of China
- Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, People's Republic of China
- The High Magnetic Field Laboratory of Anhui Province, Hefei 230031, People's Republic of China
| | - Jiyu Fan
- Department of Applied Physics, Nanjing University of Aeronautics and Astronautics, Nanjing 211106, People's Republic of China
| | - Chunlan Ma
- Jiangsu Key Laboratory of Micro and Nano Heat Fluid Flow Technology and Energy Application, School of Physical Science and Technology, Suzhou University of Science and Technology, Suzhou, 215009, People's Republic of China
| | - Li Pi
- Anhui Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, People's Republic of China
- Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, People's Republic of China
- The High Magnetic Field Laboratory of Anhui Province, Hefei 230031, People's Republic of China
| | - Lei Zhang
- Anhui Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, People's Republic of China
- The High Magnetic Field Laboratory of Anhui Province, Hefei 230031, People's Republic of China
| | - Yuheng Zhang
- Anhui Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, People's Republic of China
- Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, People's Republic of China
- The High Magnetic Field Laboratory of Anhui Province, Hefei 230031, People's Republic of China
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21
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Taupin M, Paschen S. 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] [Key Words] [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∼ k B T / 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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Affiliation(s)
- Mathieu Taupin
- Institute of Solid State Physics, Vienna University of Technology, Wiedner Hauptstr. 8-10, 1040 Vienna, Austria;
| | - Silke Paschen
- Institute of Solid State Physics, Vienna University of Technology, Wiedner Hauptstr. 8-10, 1040 Vienna, Austria;
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22
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Reiss P, Graf D, Haghighirad AA, Vojta T, Coldea AI. Signatures of a Quantum Griffiths Phase Close to an Electronic Nematic Quantum Phase Transition. PHYSICAL REVIEW LETTERS 2021; 127:246402. [PMID: 34951778 DOI: 10.1103/physrevlett.127.246402] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 10/08/2021] [Indexed: 06/14/2023]
Abstract
In the vicinity of a quantum critical point, quenched disorder can lead to a quantum Griffiths phase, accompanied by an exotic power-law scaling with a continuously varying dynamical exponent that diverges in the zero-temperature limit. Here, we investigate a nematic quantum critical point in the iron-based superconductor FeSe_{0.89}S_{0.11} using applied hydrostatic pressure. We report an unusual crossing of the magnetoresistivity isotherms in the nonsuperconducting normal state that features a continuously varying dynamical exponent over a large temperature range. We interpret our results in terms of a quantum Griffiths phase caused by nematic islands that result from the local distribution of Se and S atoms. At low temperatures, the Griffiths phase is masked by the emergence of a Fermi liquid phase due to a strong nematoelastic coupling and a Lifshitz transition that changes the topology of the Fermi surface.
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Affiliation(s)
- Pascal Reiss
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, United Kingdom
| | - David Graf
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, USA
| | - Amir A Haghighirad
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, United Kingdom
- Institute for Quantum Materials and Technologies, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
| | - Thomas Vojta
- Department of Physics, Missouri University of Science and Technology, Rolla, Missouri 65409, USA
| | - Amalia I Coldea
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, United Kingdom
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23
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Non-Fermi liquid behavior below the Néel temperature in the frustrated heavy fermion magnet UAu 2. Proc Natl Acad Sci U S A 2021; 118:2102687118. [PMID: 34873053 DOI: 10.1073/pnas.2102687118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/11/2021] [Indexed: 11/18/2022] Open
Abstract
The term Fermi liquid is almost synonymous with the metallic state. The association is known to break down at quantum critical points (QCPs), but these require precise values of tuning parameters, such as pressure and applied magnetic field, to exactly suppress a continuous phase transition temperature to the absolute zero. Three-dimensional non-Fermi liquid states, apart from superconductivity, that are unshackled from a QCP are much rarer and are not currently well understood. Here, we report that the triangular lattice system uranium diauride (UAu2) forms such a state with a non-Fermi liquid low-temperature heat capacity [Formula: see text] and electrical resistivity [Formula: see text] far below its Néel temperature. The magnetic order itself has a novel structure and is accompanied by weak charge modulation that is not simply due to magnetostriction. The charge modulation continues to grow in amplitude with decreasing temperature, suggesting that charge degrees of freedom play an important role in the non-Fermi liquid behavior. In contrast with QCPs, the heat capacity and resistivity we find are unusually resilient in magnetic field. Our results suggest that a combination of magnetic frustration and Kondo physics may result in the emergence of this novel state.
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24
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Lester C, Ramos S, Perry RS, Croft TP, Laver M, Bewley RI, Guidi T, Hiess A, Wildes A, Forgan EM, Hayden SM. Magnetic-field-controlled spin fluctuations and quantum critically in Sr 3Ru 2O 7. Nat Commun 2021; 12:5798. [PMID: 34608160 PMCID: PMC8490391 DOI: 10.1038/s41467-021-26068-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 09/14/2021] [Indexed: 11/24/2022] Open
Abstract
When the transition temperature of a continuous phase transition is tuned to absolute zero, new ordered phases and physical behaviour emerge in the vicinity of the resulting quantum critical point. Sr3Ru2O7 can be tuned through quantum criticality with magnetic field at low temperature. Near its critical field Bc it displays the hallmark T-linear resistivity and a \documentclass[12pt]{minimal}
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\begin{document}$$T\,{{{{{{\mathrm{log}}}}}}}\,(1/T)$$\end{document}Tlog(1/T) electronic heat capacity behaviour of strange metals. However, these behaviours have not been related to any critical fluctuations. Here we use inelastic neutron scattering to reveal the presence of collective spin fluctuations whose relaxation time and strength show a nearly singular variation with magnetic field as Bc is approached. The large increase in the electronic heat capacity and entropy near Bc can be understood quantitatively in terms of the scattering of conduction electrons by these spin-fluctuations. On entering the spin-density-wave ordered phase present near Bc, the fluctuations become stronger suggesting that the order is stabilised through an “order-by-disorder” mechanism. Sr3Ru2O7 exhibits a quantum critical point tunable by magnetic field and has been widely used in the study of criticality. Here, by using inelastic neutron scattering, the authors measure collective magnetic excitations near the quantum critical point and relate them to thermodynamic properties and spin density wave order.
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Affiliation(s)
- C Lester
- H.H. Wills Physics Laboratory, University of Bristol, Tyndall Ave., Bristol, BS8 1TL, UK
| | - S Ramos
- School of Physical Sciences, University of Kent, Canterbury, CT2 7NH, UK
| | - R S Perry
- London Centre for Nanotechnology, University College London, London, WC1H 0AH, UK
| | - T P Croft
- H.H. Wills Physics Laboratory, University of Bristol, Tyndall Ave., Bristol, BS8 1TL, UK
| | - M Laver
- School of Physics and Astronomy, University of Birmingham, Birmingham, BT15 2TT, UK
| | - R I Bewley
- ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, OX11 0QX, UK
| | - T Guidi
- ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, OX11 0QX, UK
| | - A Hiess
- Institut Laue-Langevin, 71 avenue des Martyrs, CS 20156, 38042, Grenoble, France.,European Spallation Source ERIC, P.O. Box 176, 22100, Lund, Sweden
| | - A Wildes
- Institut Laue-Langevin, 71 avenue des Martyrs, CS 20156, 38042, Grenoble, France
| | - E M Forgan
- School of Physics and Astronomy, University of Birmingham, Birmingham, BT15 2TT, UK
| | - S M Hayden
- H.H. Wills Physics Laboratory, University of Bristol, Tyndall Ave., Bristol, BS8 1TL, UK.
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25
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Grossman O, Hofmann JS, Holder T, Berg E. Specific Heat of a Quantum Critical Metal. PHYSICAL REVIEW LETTERS 2021; 127:017601. [PMID: 34270320 DOI: 10.1103/physrevlett.127.017601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Accepted: 05/30/2021] [Indexed: 06/13/2023]
Abstract
We investigate the specific heat c, near an Ising nematic quantum critical point (QCP), using sign problem-free quantum Monte Carlo simulations. Cooling towards the QCP, we find a broad regime of temperature where c/T is close to the value expected from the noninteracting band structure, even for a moderately large coupling strength. At lower temperature, we observe a rapid rise of c/T, followed by a drop to zero as the system becomes superconducting. The spin susceptibility begins to drop at roughly the same temperature where the enhancement of c/T onsets, most likely due to the opening of a gap associated with superconducting fluctuations. These findings suggest that superconductivity and non-Fermi liquid behavior (manifested in an enhancement of the effective mass) onset at comparable energy scales. We support these conclusions with an analytical perturbative calculation.
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Affiliation(s)
- Ori Grossman
- Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Johannes S Hofmann
- Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Tobias Holder
- Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Erez Berg
- Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot 76100, Israel
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26
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O'Neill CD, Abdul-Jabbar G, Wermeille D, Bourges P, Krüger F, Huxley AD. Field-Induced Modulated State in the Ferromagnet PrPtAl. PHYSICAL REVIEW LETTERS 2021; 126:197203. [PMID: 34047591 DOI: 10.1103/physrevlett.126.197203] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 04/13/2021] [Indexed: 06/12/2023]
Abstract
The theory of quantum order-by-disorder (QOBD) explains the formation of modulated magnetic states at the boundary between ferromagnetism and paramagnetism in zero field. PrPtAl has been argued to provide an archetype for this. Here, we report the phase diagram in magnetic field, applied along both the easy a axis and hard b axis. For field aligned to the b axis, we find that the magnetic transition temperatures are suppressed and at low temperature there is a single modulated fan state, separating an easy a axis ferromagnetic state from a field polarized state. This fan state is well explained with the QOBD theory in the presence of anisotropy and field. Experimental evidence supporting the QOBD explanation is provided by the large increase in the T^{2} coefficient of the resistivity and direct detection of enhanced magnetic fluctuations with inelastic neutron scattering, across the field range spanned by the fan state. This shows that the QOBD mechanism can explain field induced modulated states that persist to very low temperature.
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Affiliation(s)
- Christopher D O'Neill
- School of Physics and CSEC, University of Edinburgh, Edinburgh EH9 3FD, United Kingdom
| | - Gino Abdul-Jabbar
- School of Physics and CSEC, University of Edinburgh, Edinburgh EH9 3FD, United Kingdom
| | | | - Philippe Bourges
- Laboratoire Léon Brillouin (UMR12 CEA-CNRS), 91191 Gif-sur-Yvette Cedex, France
| | - Frank Krüger
- London Centre for Nanotechnology, University College London, Gordon Street, London WC1H 0AH, United Kingdom
- ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX, United Kingdom
| | - Andrew D Huxley
- School of Physics and CSEC, University of Edinburgh, Edinburgh EH9 3FD, United Kingdom
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27
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Fuhrman WT, Sidorenko A, Hänel J, Winkler H, Prokofiev A, Rodriguez-Rivera JA, Qiu Y, Blaha P, Si Q, Broholm CL, Paschen S. Pristine quantum criticality in a Kondo semimetal. SCIENCE ADVANCES 2021; 7:eabf9134. [PMID: 34138738 PMCID: PMC8133744 DOI: 10.1126/sciadv.abf9134] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Accepted: 03/30/2021] [Indexed: 06/12/2023]
Abstract
The observation of quantum criticality in diverse classes of strongly correlated electron systems has been instrumental in establishing ordering principles, discovering new phases, and identifying the relevant degrees of freedom and interactions. At focus so far have been insulators and metals. Semimetals, which are of great current interest as candidate phases with nontrivial topology, are much less explored in experiments. Here, we study the Kondo semimetal CeRu4Sn6 by magnetic susceptibility, specific heat, and inelastic neutron scattering experiments. The power-law divergence of the magnetic Grünesien ratio reveals that, unexpectedly, this compound is quantum critical without tuning. The dynamical energy over temperature scaling in the neutron response throughout the Brillouin zone and the temperature dependence of the static uniform susceptibility, indicate that temperature is the only energy scale in the criticality. Such behavior, which has been associated with Kondo destruction quantum criticality in metallic systems, could be generic in the semimetal setting.
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Affiliation(s)
- Wesley T Fuhrman
- Institute for Quantum Matter and Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, MD 21218, USA
| | - Andrey Sidorenko
- Institute of Solid State Physics, Vienna University of Technology, Wiedner Hauptstr. 8-10, 1040 Vienna, Austria
| | - Jonathan Hänel
- Institute of Solid State Physics, Vienna University of Technology, Wiedner Hauptstr. 8-10, 1040 Vienna, Austria
| | - Hannes Winkler
- Institute of Solid State Physics, Vienna University of Technology, Wiedner Hauptstr. 8-10, 1040 Vienna, Austria
| | - Andrey Prokofiev
- Institute of Solid State Physics, Vienna University of Technology, Wiedner Hauptstr. 8-10, 1040 Vienna, Austria
| | - Jose A Rodriguez-Rivera
- Department of Materials Sciences, University of Maryland, College Park, MD 20742, USA
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Yiming Qiu
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Peter Blaha
- Institute of Materials Chemistry, Vienna University of Technology, 1040 Vienna, Austria
| | - Qimiao Si
- Department of Physics and Astronomy, Rice Center for Quantum Materials, Rice University, Houston, TX 77005, USA
| | - Collin L Broholm
- Institute for Quantum Matter and Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, MD 21218, USA
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
- Department of Materials Science and Engineering, The Johns Hopkins University, Baltimore, MD 21218, USA
| | - Silke Paschen
- Institute of Solid State Physics, Vienna University of Technology, Wiedner Hauptstr. 8-10, 1040 Vienna, Austria.
- Department of Physics and Astronomy, Rice Center for Quantum Materials, Rice University, Houston, TX 77005, USA
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28
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Ni JM, Huang YY, Cheng EJ, Yu YJ, Pan BL, Li Q, Xu LM, Tian ZM, Li SY. Giant isotropic magneto-thermal conductivity of metallic spin liquid candidate Pr 2Ir 2O 7 with quantum criticality. Nat Commun 2021; 12:307. [PMID: 33436565 PMCID: PMC7804409 DOI: 10.1038/s41467-020-20562-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Accepted: 12/09/2020] [Indexed: 12/05/2022] Open
Abstract
Spin liquids are exotic states with no spontaneous symmetry breaking down to zero-temperature because of the highly entangled and fluctuating spins in frustrated systems. Exotic excitations like magnetic monopoles, visons, and photons may emerge from quantum spin ice states, a special kind of spin liquids in pyrochlore lattices. These materials usually are insulators, with an exception of the pyrochlore iridate Pr2Ir2O7, which was proposed as a metallic spin liquid located at a zero-field quantum critical point. Here we report the ultralow-temperature thermal conductivity measurements on Pr2Ir2O7. The Wiedemann-Franz law is verified at high fields and inferred at zero field, suggesting no breakdown of Landau quasiparticles at the quantum critical point, and the absence of mobile fermionic excitations. This result puts strong constraints on the description of the quantum criticality in Pr2Ir2O7. Unexpectedly, although the specific heats are anisotropic with respect to magnetic field directions, the thermal conductivities display the giant but isotropic response. This indicates that quadrupolar interactions and quantum fluctuations are important, which will help determine the true ground state of this material.
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Affiliation(s)
- J M Ni
- State Key Laboratory of Surface Physics, Department of Physics, and Laboratory of Advanced Materials, Fudan University, Shanghai, 200438, China
| | - Y Y Huang
- State Key Laboratory of Surface Physics, Department of Physics, and Laboratory of Advanced Materials, Fudan University, Shanghai, 200438, China
| | - E J Cheng
- State Key Laboratory of Surface Physics, Department of Physics, and Laboratory of Advanced Materials, Fudan University, Shanghai, 200438, China
| | - Y J Yu
- State Key Laboratory of Surface Physics, Department of Physics, and Laboratory of Advanced Materials, Fudan University, Shanghai, 200438, China
| | - B L Pan
- State Key Laboratory of Surface Physics, Department of Physics, and Laboratory of Advanced Materials, Fudan University, Shanghai, 200438, China
| | - Q Li
- State Key Laboratory of Surface Physics, Department of Physics, and Laboratory of Advanced Materials, Fudan University, Shanghai, 200438, China
| | - L M Xu
- School of Physics, and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Z M Tian
- School of Physics, and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan, 430074, China.
| | - S Y Li
- State Key Laboratory of Surface Physics, Department of Physics, and Laboratory of Advanced Materials, Fudan University, Shanghai, 200438, China.
- Collaborative Innovation Center of Advanced Microstructures, Nanjing, 210093, China.
- Shanghai Research Center for Quantum Sciences, Shanghai, 201315, China.
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29
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Mishra S, Hornung J, Raba M, Klotz J, Förster T, Harima H, Aoki D, Wosnitza J, McCollam A, Sheikin I. Robust Fermi-Surface Morphology of CeRhIn_{5} across the Putative Field-Induced Quantum Critical Point. PHYSICAL REVIEW LETTERS 2021; 126:016403. [PMID: 33480764 DOI: 10.1103/physrevlett.126.016403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 11/18/2020] [Accepted: 12/15/2020] [Indexed: 06/12/2023]
Abstract
We report a comprehensive de Haas-van Alphen (dHvA) study of the heavy-fermion material CeRhIn_{5} in magnetic fields up to 70 T. Several dHvA frequencies gradually emerge at high fields as a result of magnetic breakdown. Among them is the thermodynamically important β_{1} branch, which has not been observed so far. Comparison of our angle-dependent dHvA spectra with those of the non-4f compound LaRhIn_{5} and with band-structure calculations evidences that the Ce 4f electrons in CeRhIn_{5} remain localized over the whole field range. This rules out any significant Fermi-surface reconstruction, either at the suggested nematic phase transition at B^{*}≈30 T or at the putative quantum critical point at B_{c}≃50 T. Our results rather demonstrate the robustness of the Fermi surface and the localized nature of the 4f electrons inside and outside of the antiferromagnetic phase.
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Affiliation(s)
- S Mishra
- Laboratoire National des Champs Magnétiques Intenses (LNCMI-EMFL), CNRS, UGA, 38042 Grenoble, France
| | - J Hornung
- Hochfeld-Magnetlabor Dresden (HLD-EMFL) and Würzburg-Dresden Cluster of Excellence ct.qmat, Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany
- Institut für Festkörper- und Materialphysik, TU Dresden, 01062 Dresden, Germany
| | - M Raba
- Laboratoire National des Champs Magnétiques Intenses (LNCMI-EMFL), CNRS, UGA, 38042 Grenoble, France
| | - J Klotz
- Hochfeld-Magnetlabor Dresden (HLD-EMFL) and Würzburg-Dresden Cluster of Excellence ct.qmat, Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany
| | - T Förster
- Hochfeld-Magnetlabor Dresden (HLD-EMFL) and Würzburg-Dresden Cluster of Excellence ct.qmat, Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany
| | - H Harima
- Graduate School of Science, Kobe University, Kobe 657-8501, Japan
| | - D Aoki
- Institute for Materials Research, Tohoku University, Oarai, Ibaraki, 311-1313, Japan
| | - J Wosnitza
- Hochfeld-Magnetlabor Dresden (HLD-EMFL) and Würzburg-Dresden Cluster of Excellence ct.qmat, Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany
- Institut für Festkörper- und Materialphysik, TU Dresden, 01062 Dresden, Germany
| | - A McCollam
- High Field Magnet Laboratory (HFML-EMFL), Radboud University, 6525 ED Nijmegen, The Netherlands
| | - I Sheikin
- Laboratoire National des Champs Magnétiques Intenses (LNCMI-EMFL), CNRS, UGA, 38042 Grenoble, France
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30
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Danu B, Vojta M, Assaad FF, Grover T. Kondo Breakdown in a Spin-1/2 Chain of Adatoms on a Dirac Semimetal. PHYSICAL REVIEW LETTERS 2020; 125:206602. [PMID: 33258629 DOI: 10.1103/physrevlett.125.206602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 10/02/2020] [Indexed: 06/12/2023]
Abstract
We consider a spin-1/2 Heisenberg chain coupled via a Kondo interaction to two-dimensional Dirac fermions. The Kondo interaction is irrelevant at the decoupled fixed point, leading to the existence of a Kondo-breakdown phase and a Kondo-breakdown critical point separating such a phase from a heavy Fermi liquid. We reach this conclusion on the basis of a renormalization group analysis, large-N calculations as well as extensive auxiliary-field quantum Monte Carlo simulations. We extract quantities such as the zero-bias tunneling conductance which will be relevant to future experiments involving adatoms on semimetals such as graphene.
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Affiliation(s)
- Bimla Danu
- Institut für Theoretische Physik und Astrophysik and Würzburg-Dresden Cluster of Excellence ct.qmat, Universität Würzburg, 97074 Würzburg, Germany
| | - Matthias Vojta
- Institut für Theoretische Physik and Würzburg-Dresden Cluster of Excellence ct.qmat, Technische Universität Dresden, 01062 Dresden, Germany
| | - Fakher F Assaad
- Institut für Theoretische Physik und Astrophysik and Würzburg-Dresden Cluster of Excellence ct.qmat, Universität Würzburg, 97074 Würzburg, Germany
| | - Tarun Grover
- Department of Physics, University of California at San Diego, La Jolla, California 92093, USA
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31
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Magnon Bose-Einstein condensation and superconductivity in a frustrated Kondo lattice. Proc Natl Acad Sci U S A 2020; 117:20462-20467. [PMID: 32788363 DOI: 10.1073/pnas.2000501117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Motivated by recent experiments on magnetically frustrated heavy fermion metals, we theoretically study the phase diagram of the Kondo lattice model with a nonmagnetic valence bond solid ground state on a ladder. A similar physical setting may be naturally occurring in [Formula: see text], [Formula: see text], and [Formula: see text] compounds. In the insulating limit, the application of a magnetic field drives a quantum phase transition to an easy-plane antiferromagnet, which is described by a Bose-Einstein condensation of magnons. Using a combination of field theoretical techniques and density matrix renormalization group calculations we demonstrate that in one dimension this transition is stable in the presence of a metallic Fermi sea, and its universality class in the local magnetic response is unaffected by the itinerant gapless fermions. Moreover, we find that fluctuations about the valence bond solid ground state can mediate an attractive interaction that drives unconventional superconducting correlations. We discuss the extensions of our findings to higher dimensions and argue that depending on the filling of conduction electrons, the magnon Bose-Einstein condensation transition can remain stable in a metal also in dimensions two and three.
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32
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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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33
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Valenta J, Naka T, Diviš M, Vališka M, Proschek P, Vlášková K, Klicpera M, Prokleška J, Custers J, Prchal J. Impact of isoelectronic substitution and hydrostatic pressure on the quantum critical properties of CeRhSi 3. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:425601. [PMID: 32585641 DOI: 10.1088/1361-648x/aba015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2020] [Accepted: 06/25/2020] [Indexed: 06/11/2023]
Abstract
There is an ongoing dispute in the community about the absence of a magnetic quantum critical point (QCP) in the noncentrosymmetric heavy fermion compound CeRhSi3. In order to explore this question we prepared single crystals of CeRh(Si1-xGex)3withx= 0.05 and 0.15 and determined the temperature-pressure (T-p) phase diagram by means of measurements of the electrical resistivity. The substitution of isoelectronic but large Ge enforces a lattice volume increase resulting in a weakening of the Kondo interaction. As a result, thex= 0.05 andx= 0.15 compound exhibit a transition into the antiferromagnetic (AFM) at higher temperatures beingTN= 4.7 K andTN1= 19.7 K, respectively. Application of pressure suppressesTN(TN1) monotonically and pressure induced superconductivity is observed in both Ge-substituted compounds abovep⩾ 2.16 GPa (x= 0.05) andp⩾ 2.93 GPa (x= 0.15). Extrapolation ofTN(p) → 0 of CeRh(Si0.95Ge0.05)3yields a critical pressure ofpc≈ 3.4 GPa (in CeRh(Si0.85Ge0.15)3 pc≈ 3.5 GPa) pointing to the presence of an AFM QCP located deep inside the superconducting state.
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Affiliation(s)
- J Valenta
- Charles University, Faculty of Mathematics and Physics, Department of Condensed Matter Physics, Ke Karlovu 5, 121 16 Prague 2, Czech Republic
| | - T Naka
- National Institute for Materials Science, Research Center for Functional Materials, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan
| | - M Diviš
- Charles University, Faculty of Mathematics and Physics, Department of Condensed Matter Physics, Ke Karlovu 5, 121 16 Prague 2, Czech Republic
| | - M Vališka
- Charles University, Faculty of Mathematics and Physics, Department of Condensed Matter Physics, Ke Karlovu 5, 121 16 Prague 2, Czech Republic
| | - P Proschek
- Charles University, Faculty of Mathematics and Physics, Department of Condensed Matter Physics, Ke Karlovu 5, 121 16 Prague 2, Czech Republic
| | - K Vlášková
- Charles University, Faculty of Mathematics and Physics, Department of Condensed Matter Physics, Ke Karlovu 5, 121 16 Prague 2, Czech Republic
| | - M Klicpera
- Charles University, Faculty of Mathematics and Physics, Department of Condensed Matter Physics, Ke Karlovu 5, 121 16 Prague 2, Czech Republic
| | - J Prokleška
- Charles University, Faculty of Mathematics and Physics, Department of Condensed Matter Physics, Ke Karlovu 5, 121 16 Prague 2, Czech Republic
| | - J Custers
- Charles University, Faculty of Mathematics and Physics, Department of Condensed Matter Physics, Ke Karlovu 5, 121 16 Prague 2, Czech Republic
| | - J Prchal
- Charles University, Faculty of Mathematics and Physics, Department of Condensed Matter Physics, Ke Karlovu 5, 121 16 Prague 2, Czech Republic
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34
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Non-monotonic pressure dependence of high-field nematicity and magnetism in CeRhIn 5. Nat Commun 2020; 11:3482. [PMID: 32661299 PMCID: PMC7359027 DOI: 10.1038/s41467-020-17274-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2020] [Accepted: 06/22/2020] [Indexed: 11/28/2022] Open
Abstract
CeRhIn5 provides a textbook example of quantum criticality in a heavy fermion system: Pressure suppresses local-moment antiferromagnetic (AFM) order and induces superconductivity in a dome around the associated quantum critical point (QCP) near pc ≈ 23 kbar. Strong magnetic fields also suppress the AFM order at a field-induced QCP at Bc ≈ 50 T. In its vicinity, a nematic phase at B* ≈ 28 T characterized by a large in-plane resistivity anisotropy emerges. Here, we directly investigate the interrelation between these phenomena via magnetoresistivity measurements under high pressure. As pressure increases, the nematic transition shifts to higher fields, until it vanishes just below pc. While pressure suppresses magnetic order in zero field as pc is approached, we find magnetism to strengthen under strong magnetic fields due to suppression of the Kondo effect. We reveal a strongly non-mean-field-like phase diagram, much richer than the common local-moment description of CeRhIn5 would suggest. Multiple quantum critical behaviors exist in the heavy fermion material CeRhIn5, but their interrelation is less studied. Here, Helm et al. investigate the interrelation of two quantum critical points and other relevant orders, revealing a strongly non-mean-field-like phase diagram.
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35
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Kirkpatrick TR, Belitz D. Ferromagnetic Quantum Critical Point in Noncentrosymmetric Systems. PHYSICAL REVIEW LETTERS 2020; 124:147201. [PMID: 32338989 DOI: 10.1103/physrevlett.124.147201] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Accepted: 03/06/2020] [Indexed: 06/11/2023]
Abstract
Ferromagnetic quantum criticality in clean metals has proven elusive due to fermionic soft modes that drive the transition first order. We show that noncentrosymmetric metals with a strong spin-orbit interaction provide a promising class of materials for realizing a ferromagnetic quantum critical point in clean systems. The spin-orbit interaction renders massive the soft modes that interfere with quantum criticality in most materials, while the absence of spatial inversion symmetry precludes the existence of new classes of soft modes that could have the same effect.
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Affiliation(s)
- T R Kirkpatrick
- Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742, USA
| | - D Belitz
- Department of Physics and Institute of Theoretical Science, University of Oregon, Eugene, Oregon 97403, USA
- Materials Science Institute, University of Oregon, Eugene, Oregon 97403, USA
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36
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Song M, Xian C, Wang Y, Song J, Li Z, Ling L, Zhang L, Han Y, Cao L, Xiong Y. Disorder-driven non-Fermi liquid behavior in itinerant ferromagnet α-Co 5Ge 3. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:155802. [PMID: 31846939 DOI: 10.1088/1361-648x/ab62be] [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
The physical properties of itinerant ferromagnet [Formula: see text]-Co5Ge3 with both strong disorder and spin fluctuations was studied. The dc and ac susceptibility show that both spin fluctuations and disorder dominate the physical properties. In the spin glass phase, with a coexisting ferromagnetic state ([Formula: see text]30 K), both non-Fermi liquid behavior and large exponent of scaling relation of [Formula: see text] are observed and attributed to the spin fluctuations and disorder induced by cobalt defects. Upon the increase of external field, Fermi liquid behavior restores due to the suppression of spin fluctuations and disorder. In addition, a large anomalous Hall coefficient R s is observed. Our results suggest that [Formula: see text]-Co5Ge3 is a typical itinerant ferromagnet to explore the interplay of disorder and spin fluctuations.
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Affiliation(s)
- Meng Song
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory of the Chinese Academy of Sciences, Hefei, Anhui 230031, People's Republic of China. University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
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37
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Observation of an antiferromagnetic quantum critical point in high-purity LaNiO 3. Nat Commun 2020; 11:1402. [PMID: 32179750 PMCID: PMC7075863 DOI: 10.1038/s41467-020-15143-w] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Accepted: 02/16/2020] [Indexed: 11/16/2022] Open
Abstract
Amongst the rare-earth perovskite nickelates, LaNiO3 (LNO) is an exception. While the former have insulating and antiferromagnetic ground states, LNO remains metallic and non-magnetic down to the lowest temperatures. It is believed that LNO is a strange metal, on the verge of an antiferromagnetic instability. Our work suggests that LNO is a quantum critical metal, close to an antiferromagnetic quantum critical point (QCP). The QCP behavior in LNO is manifested in epitaxial thin films with unprecedented high purities. We find that the temperature and magnetic field dependences of the resistivity of LNO at low temperatures are consistent with scatterings of charge carriers from weak disorder and quantum fluctuations of an antiferromagnetic nature. Furthermore, we find that the introduction of a small concentration of magnetic impurities qualitatively changes the magnetotransport properties of LNO, resembling that found in some heavy-fermion Kondo lattice systems in the vicinity of an antiferromagnetic QCP. LaNiO3 is a strange metal, for reasons that are not well understood. Here, Liu et al. report evidence for scattering of charge carriers by antiferromagnetic quantum fluctuations in high-purity epitaxial thin films of LaNiO3, suggesting it is close to an antiferromagnetic quantum critical point.
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38
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Arpaia R, Caprara S, Fumagalli R, De Vecchi G, Peng YY, Andersson E, Betto D, De Luca GM, Brookes NB, Lombardi F, Salluzzo M, Braicovich L, Di Castro C, Grilli M, Ghiringhelli G. Dynamical charge density fluctuations pervading the phase diagram of a Cu-based high- T c superconductor. Science 2020; 365:906-910. [PMID: 31467219 DOI: 10.1126/science.aav1315] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Accepted: 07/30/2019] [Indexed: 11/02/2022]
Abstract
Charge density modulations have been observed in all families of high-critical temperature (T c) superconducting cuprates. Although they are consistently found in the underdoped region of the phase diagram and at relatively low temperatures, it is still unclear to what extent they influence the unusual properties of these systems. Using resonant x-ray scattering, we carefully determined the temperature dependence of charge density modulations in YBa2Cu3O7-δ and Nd1+ x Ba2- x Cu3O7-δ for several doping levels. We isolated short-range dynamical charge density fluctuations in addition to the previously known quasi-critical charge density waves. They persist up to well above the pseudogap temperature T*, are characterized by energies of a few milli-electron volts, and pervade a large area of the phase diagram.
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Affiliation(s)
- R Arpaia
- Dipartimento di Fisica, Politecnico di Milano, I-20133 Milano, Italy. .,Quantum Device Physics Laboratory, Department of Microtechnology and Nanoscience, Chalmers University of Technology, SE-41296 Göteborg, Sweden
| | - S Caprara
- Dipartimento di Fisica, Università di Roma "La Sapienza," I-00185 Roma, Italy.,CNR-ISC, I-00185 Roma, Italy
| | - R Fumagalli
- Dipartimento di Fisica, Politecnico di Milano, I-20133 Milano, Italy
| | - G De Vecchi
- Dipartimento di Fisica, Politecnico di Milano, I-20133 Milano, Italy
| | - Y Y Peng
- Dipartimento di Fisica, Politecnico di Milano, I-20133 Milano, Italy
| | - E Andersson
- Quantum Device Physics Laboratory, Department of Microtechnology and Nanoscience, Chalmers University of Technology, SE-41296 Göteborg, Sweden
| | - D Betto
- ESRF, European Synchrotron, F-38043 Grenoble, France
| | - G M De Luca
- Dipartimento di Fisica "E. Pancini," Università di Napoli Federico II, Complesso Monte Sant'Angelo, I-80126 Napoli, Italy.,CNR-SPIN, Complesso Monte Sant'Angelo, I-80126 Napoli, Italy
| | - N B Brookes
- ESRF, European Synchrotron, F-38043 Grenoble, France
| | - F Lombardi
- Quantum Device Physics Laboratory, Department of Microtechnology and Nanoscience, Chalmers University of Technology, SE-41296 Göteborg, Sweden
| | - M Salluzzo
- CNR-SPIN, Complesso Monte Sant'Angelo, I-80126 Napoli, Italy
| | - L Braicovich
- Dipartimento di Fisica, Politecnico di Milano, I-20133 Milano, Italy.,ESRF, European Synchrotron, F-38043 Grenoble, France
| | - C Di Castro
- Dipartimento di Fisica, Università di Roma "La Sapienza," I-00185 Roma, Italy.,CNR-ISC, I-00185 Roma, Italy
| | - M Grilli
- Dipartimento di Fisica, Università di Roma "La Sapienza," I-00185 Roma, Italy.,CNR-ISC, I-00185 Roma, Italy
| | - G Ghiringhelli
- Dipartimento di Fisica, Politecnico di Milano, I-20133 Milano, Italy. .,CNR-SPIN, Dipartimento di Fisica, Politecnico di Milano, I-20133 Milano, Italy
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39
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Abstract
The bilayer perovskite Sr3Ru2O7 has been widely studied as a canonical strange metal. It exhibits T-linear resistivity and a T log(1/T) electronic specific heat in a field-tuned quantum critical fan. Criticality is known to occur in "hot" Fermi pockets with a high density of states close to the Fermi energy. We show that while these hot pockets occupy a small fraction of the Brillouin zone, they are responsible for the anomalous transport and thermodynamics of the material. Specifically, a scattering process in which two electrons from the large, "cold" Fermi surfaces scatter into one hot and one cold electron renders the ostensibly noncritical cold fermions a marginal Fermi liquid. From this fact the transport and thermodynamic phase diagram is reproduced in detail. Finally, we show that the same scattering mechanism into hot electrons that are instead localized near a 2D van Hove singularity explains the anomalous transport observed in strained Sr2RuO4.
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Affiliation(s)
| | - Erez Berg
- Department of Condensed Matter Physics, The Weizmann Institute of Science, Rehovot 76100, Israel;
| | - Sean A Hartnoll
- Department of Physics, Stanford University, Stanford, CA 94305
- Stanford Institute for Materials and Energy Science, SLAC National Accelerator Laboratory, Menlo Park, CA 94025
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40
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Cai A, Yu Z, Hu H, Kirchner S, Si Q. Dynamical Scaling of Charge and Spin Responses at a Kondo Destruction Quantum Critical Point. PHYSICAL REVIEW LETTERS 2020; 124:027205. [PMID: 32004044 DOI: 10.1103/physrevlett.124.027205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2019] [Indexed: 06/10/2023]
Abstract
Quantum critical points often arise in metals perched at the border of an antiferromagnetic order. The recent observation of singular and dynamically scaling charge conductivity in an antiferromagnetic quantum critical heavy fermion metal implicates beyond-Landau quantum criticality. Here we study the charge and spin dynamics of a Kondo destruction quantum critical point (QCP), as realized in an SU(2)-symmetric Bose-Fermi Kondo model. We find that the critical exponents and scaling functions of the spin and single-particle responses of the QCP in the SU(2) case are essentially the same as those of the large-N limit, showing that 1/N corrections are subleading. Building on this insight, we demonstrate that the charge responses at the Kondo destruction QCP are singular and obey ω/T scaling. This property persists at the Kondo destruction QCP of the SU(2)-symmetric Kondo lattice model.
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Affiliation(s)
- Ang Cai
- Department of Physics and Astronomy, Rice Center for Quantum Materials, Rice University, Houston, Texas 77005, USA
| | - Zuodong Yu
- Zhejiang Institute of Modern Physics, Zhejiang University, Hangzhou, Zhejiang 310058, China
- Zhejiang Province Key Laboratory of Quantum Technology and Devices, Zhejiang University, Hangzhou 310027, China
| | - Haoyu Hu
- Department of Physics and Astronomy, Rice Center for Quantum Materials, Rice University, Houston, Texas 77005, USA
| | - Stefan Kirchner
- Zhejiang Institute of Modern Physics, Zhejiang University, Hangzhou, Zhejiang 310058, China
- Zhejiang Province Key Laboratory of Quantum Technology and Devices, Zhejiang University, Hangzhou 310027, China
| | - Qimiao Si
- Department of Physics and Astronomy, Rice Center for Quantum Materials, Rice University, Houston, Texas 77005, USA
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Prochaska L, Li X, MacFarland DC, Andrews AM, Bonta M, Bianco EF, Yazdi S, Schrenk W, Detz H, Limbeck A, Si Q, Ringe E, Strasser G, Kono J, Paschen S. Singular charge fluctuations at a magnetic quantum critical point. Science 2020; 367:285-288. [DOI: 10.1126/science.aag1595] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 09/07/2019] [Accepted: 12/05/2019] [Indexed: 11/02/2022]
Affiliation(s)
- L. Prochaska
- Institute of Solid State Physics, Technischen Universität (TU) Wien, Wiedner Hauptstraße 8-10, 1040 Vienna, Austria
| | - X. Li
- Department of Electrical and Computer Engineering, 6100 Main Street, Rice University, Houston, TX 77005, USA
| | - D. C. MacFarland
- Institute of Solid State Physics, Technischen Universität (TU) Wien, Wiedner Hauptstraße 8-10, 1040 Vienna, Austria
- Institute of Solid State Electronics, TU Wien, Nanocenter Campus Gußhaus, Gußhausstraße 25-25a, Gebäude CH, 1040 Vienna, Austria
| | - A. M. Andrews
- Institute of Solid State Electronics, TU Wien, Nanocenter Campus Gußhaus, Gußhausstraße 25-25a, Gebäude CH, 1040 Vienna, Austria
| | - M. Bonta
- Institute of Chemical Technologies and Analytics, TU Wien, Getreidemarkt 9, 1060 Vienna, Austria
| | - E. F. Bianco
- Department of Chemistry, 6100 Main Street, Rice University, Houston, TX 77005, USA
| | - S. Yazdi
- Department of Materials Science and Nanoengineering, 6100 Main Street, Rice University, Houston, TX 77005, USA
| | - W. Schrenk
- Center for Micro- and Nanostructures, TU Wien, Nanocenter Campus Gußhaus, Gußhausstraße 25-25a, Gebäude CH, 1040 Vienna, Austria
| | - H. Detz
- Center for Micro- and Nanostructures, TU Wien, Nanocenter Campus Gußhaus, Gußhausstraße 25-25a, Gebäude CH, 1040 Vienna, Austria
| | - A. Limbeck
- Institute of Chemical Technologies and Analytics, TU Wien, Getreidemarkt 9, 1060 Vienna, Austria
| | - Q. Si
- Department of Physics and Astronomy, Center for Quantum Materials, 6100 Main Street, Rice University, Houston, TX 77005, USA
| | - E. Ringe
- Department of Materials Science and Nanoengineering, 6100 Main Street, Rice University, Houston, TX 77005, USA
| | - G. Strasser
- Institute of Solid State Electronics, TU Wien, Nanocenter Campus Gußhaus, Gußhausstraße 25-25a, Gebäude CH, 1040 Vienna, Austria
- Center for Micro- and Nanostructures, TU Wien, Nanocenter Campus Gußhaus, Gußhausstraße 25-25a, Gebäude CH, 1040 Vienna, Austria
| | - J. Kono
- Department of Electrical and Computer Engineering, 6100 Main Street, Rice University, Houston, TX 77005, USA
- Department of Materials Science and Nanoengineering, 6100 Main Street, Rice University, Houston, TX 77005, USA
- Department of Physics and Astronomy, Center for Quantum Materials, 6100 Main Street, Rice University, Houston, TX 77005, USA
| | - S. Paschen
- Institute of Solid State Physics, Technischen Universität (TU) Wien, Wiedner Hauptstraße 8-10, 1040 Vienna, Austria
- Department of Physics and Astronomy, Center for Quantum Materials, 6100 Main Street, Rice University, Houston, TX 77005, USA
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Theory of correlated insulating behaviour and spin-triplet superconductivity in twisted double bilayer graphene. Nat Commun 2019; 10:5333. [PMID: 31767862 PMCID: PMC6877569 DOI: 10.1038/s41467-019-12981-1] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2019] [Accepted: 10/11/2019] [Indexed: 11/26/2022] Open
Abstract
Two graphene monolayers twisted by a small magic angle exhibit nearly flat bands, leading to correlated electronic states. Here we study a related but different system with reduced symmetry - twisted double bilayer graphene (TDBG), consisting of two Bernal stacked bilayer graphenes, twisted with respect to one another. Unlike the monolayer case, we show that isolated flat bands only appear on application of a vertical displacement field. We construct a phase diagram as a function of twist angle and displacement field, incorporating interactions via a Hartree-Fock approximation. At half-filling, ferromagnetic insulators are stabilized with valley Chern number \documentclass[12pt]{minimal}
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\begin{document}$${C}_{{\rm{v}}}=\pm 2$$\end{document}Cv=±2. Upon doping, ferromagnetic fluctuations are argued to lead to spin-triplet superconductivity from pairing between opposite valleys. We highlight a novel orbital effect arising from in-plane fields plays an important role in interpreting experiments. Combined with recent experimental findings, our results establish TDBG as a tunable platform to realize rare phases in conventional solids. Twisted bilayer graphene exhibits correlated electronic phases and superconductivity, but its precise nature is under debate. Here, Lee and Khalaf et al. study a twisted double bilayer graphene, where ferromagnetic insulator and spin triplet superconducting phases can be stabilized.
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Abstract
In this paper, we formulate and quantitatively examine the effect of dissipation on topological systems. We use a specific model of Kitaev quantum wire with an onsite Ohmic dissipation and perform a numerically exact method to investigate the effect of dissipation on the topological features of the system (e.g., the Majorana edge mode) at zero temperature. We find that even though the topological phase is robust against weak dissipation as it is supposed to be, it will eventually be destroyed by sufficiently strong dissipation via either a continuous quantum phase transition or a crossover depending on the symmetry of the system. The dissipation-driven quantum criticality has also been discussed. Dissipation can destroy topological phase either by phase transitions or by crossovers
The phase transitions or crossovers are determined by the symmetry of system
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Xu XY, Hong Liu Z, Pan G, Qi Y, Sun K, Meng ZY. Revealing fermionic quantum criticality from new Monte Carlo techniques. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:463001. [PMID: 31425147 DOI: 10.1088/1361-648x/ab3295] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
This review summarizes recent developments in the study of fermionic quantum criticality, focusing on new progress in numerical methodologies, especially quantum Monte Carlo methods, and insights that emerged from recently large-scale numerical simulations. Quantum critical phenomena in fermionic systems have attracted decades of extensive research efforts, partially lured by their exotic properties and potential technology applications, and partially awakened by the profound and universal fundamental principles that govern these quantum critical systems. Due to the complex and non-perturbative nature, these systems face the most difficult and challenging problems in the study of modern condensed matter physics, and many important fundamental problems remain open. Recently, new developments in model design and algorithm improvements enabled unbiased large-scale numerical solutions to be achieved in the close vicinity of these quantum critical points, which paves a new pathway towards achieving controlled conclusions through combined efforts of theoretical and numerical studies, as well as possible theoretical guidance for experiments in heavy-fermion compounds, Cu-based and Fe-based superconductors, ultra-cold fermionic atomic gas, twisted graphene layers, etc, where signatures of fermionic quantum criticality exist.
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Affiliation(s)
- Xiao Yan Xu
- Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, People's Republic of China
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45
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Okamoto S, Egami T, Nagaosa N. Critical Spin Fluctuation Mechanism for the Spin Hall Effect. PHYSICAL REVIEW LETTERS 2019; 123:196603. [PMID: 31765189 DOI: 10.1103/physrevlett.123.196603] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Revised: 08/10/2019] [Indexed: 06/10/2023]
Abstract
We propose mechanisms for the spin Hall effect in metallic systems arising from the coupling between conduction electrons and local magnetic moments that are dynamically fluctuating. Both a side-jump-type mechanism and a skew-scattering-type mechanism are considered. In either case, dynamical spin fluctuation gives rise to a nontrivial temperature dependence in the spin Hall conductivity. This leads to the enhancement in the spin Hall conductivity at nonzero temperatures near the ferromagnetic instability. The proposed mechanisms could be observed in 4d or 5d metallic compounds.
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Affiliation(s)
- Satoshi Okamoto
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Takeshi Egami
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
- Department of Materials Science and Engineering, The University of Tennessee, Knoxville, Tennessee 37996, USA
- Department of Physics and Astronomy, The University of Tennessee, Knoxville, Tennessee 37996, USA
| | - Naoto Nagaosa
- Department of Applied Physics, The University of Tokyo, Bunkyo-ku, Tokyo 113-8656, Japan
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama 351-0198, Japan
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46
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Kiselev EI, Schmalian J. Lévy Flights and Hydrodynamic Superdiffusion on the Dirac Cone of Graphene. PHYSICAL REVIEW LETTERS 2019; 123:195302. [PMID: 31765178 DOI: 10.1103/physrevlett.123.195302] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Indexed: 06/10/2023]
Abstract
We show that the hydrodynamic collision processes of graphene electrons at the neutrality point can be described in terms of a Fokker-Planck equation with a fractional derivative, corresponding to a Lévy flight in momentum space. Thus, electron-electron collisions give rise to frequent small-angle scattering processes that are interrupted by rare large-angle events. The latter give rise to superdiffusive dynamics of collective excitations. We argue that such superdiffusive dynamics is of more general importance to the out-of-equilibrium dynamics of quantum-critical systems.
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Affiliation(s)
- Egor I Kiselev
- Institut für Theorie der Kondensierten Materie, Karlsruher Institut für Technologie, 76131 Karlsruhe, Germany
| | - Jörg Schmalian
- Institut für Theorie der Kondensierten Materie, Karlsruher Institut für Technologie, 76131 Karlsruhe, Germany
- Institut für Festkörperphysik, Karlsruher Institut für Technologie, 76131 Karlsruhe, Germany
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Giannakis I, Leshen J, Kavai M, Ran S, Kang CJ, Saha SR, Zhao Y, Xu Z, Lynn JW, Miao L, Wray LA, Kotliar G, Butch NP, Aynajian P. Orbital-selective Kondo lattice and enigmatic f electrons emerging from inside the antiferromagnetic phase of a heavy fermion. SCIENCE ADVANCES 2019; 5:eaaw9061. [PMID: 31667341 PMCID: PMC6799987 DOI: 10.1126/sciadv.aaw9061] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Accepted: 09/25/2019] [Indexed: 05/25/2023]
Abstract
Novel electronic phenomena frequently form in heavy-fermions because of the mutual localized and itinerant nature of f-electrons. On the magnetically ordered side of the heavy-fermion phase diagram, f-moments are expected to be localized and decoupled from the Fermi surface. It remains ambiguous whether Kondo lattice can develop inside the magnetically ordered phase. Using spectroscopic imaging with scanning tunneling microscope, complemented by neutron scattering, x-ray absorption spectroscopy, and dynamical mean field theory, we probe the electronic states in antiferromagnetic USb2. We visualize a large gap in the antiferromagnetic phase within which Kondo hybridization develops below ~80 K. Our calculations indicate the antiferromagnetism and Kondo lattice to reside predominantly on different f-orbitals, promoting orbital selectivity as a new conception into how these phenomena coexist in heavy-fermions. Finally, at 45 K, we find a novel first order-like transition through abrupt emergence of nontrivial 5f-electronic states that may resemble the "hidden-order" phase of URu2Si2.
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Affiliation(s)
- Ioannis Giannakis
- Department of Physics, Applied Physics, and Astronomy, Binghamton University, Binghamton, NY 13902, USA
| | - Justin Leshen
- Department of Physics, Applied Physics, and Astronomy, Binghamton University, Binghamton, NY 13902, USA
| | - Mariam Kavai
- Department of Physics, Applied Physics, and Astronomy, Binghamton University, Binghamton, NY 13902, USA
| | - Sheng Ran
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
- Center for Nanophysics and Advanced Materials, Department of Physics, University of Maryland, College Park, MD 20742, USA
| | - Chang-Jong Kang
- Department of Physics and Astronomy, Rutgers University, NJ 08854, USA
| | - Shanta R. Saha
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
- Center for Nanophysics and Advanced Materials, Department of Physics, University of Maryland, College Park, MD 20742, USA
| | - Y. Zhao
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
- Department of Materials Science and Engineering, University of Maryland, College Park, MD 20742, USA
| | - Z. Xu
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - J. W. Lynn
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Lin Miao
- Department of Physics, New York University, New York, NY 10003, USA
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - L. Andrew Wray
- Department of Physics, New York University, New York, NY 10003, USA
| | - Gabriel Kotliar
- Department of Physics and Astronomy, Rutgers University, NJ 08854, USA
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, NY 11973, USA
| | - Nicholas P. Butch
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
- Center for Nanophysics and Advanced Materials, Department of Physics, University of Maryland, College Park, MD 20742, USA
| | - Pegor Aynajian
- Department of Physics, Applied Physics, and Astronomy, Binghamton University, Binghamton, NY 13902, USA
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Abstract
Electric polarization due to polar structural distortion is a central characteristic of an ferroelectric (FE) material, which is normally unattainable in a metallic system because itinerant electrons screen the internal electric field. A possible exception for a polar metal is if the itinerant electrons are decoupled with FE distortion, as proposed by Anderson and Blount. Here, we reveal an unusual FE phase transition in recently discovered polar metal LiOsO3, different from the typical transition in insulating FEs, with dramatic temperature-dependent electron−phonon coupling. Our results provide a look at models for FE transitions with the interplay between FE dipoles and itinerant electrons, suggesting that an improvement of the Anderson and Blount model is needed. Ferroelectric (FE) distortions in a metallic material were believed to be experimentally inaccessible because itinerant electrons would screen the long-range Coulomb interactions that favor a polar structure. It has been suggested by Anderson and Blount [P. W. Anderson, E. I. Blount, Phys. Rev. Lett. 14, 217−219 (1965)] that a transition from paraelectric phase to FE phase is possible for a metal if, in the paraelectric phase, the electrons at the Fermi level are decoupled from the soft transverse optical phonons, which lead to ferroelectricity. Here, using Raman spectroscopy combined with magnetotransport measurements on a recently discovered FE metal LiOsO3, we demonstrate active interplay of itinerant electrons and the FE order: Itinerant electrons cause strong renormalization of the FE order parameter, leading to a more gradual transition in LiOsO3 than typical insulating FEs. In return, the FE order enhances the anisotropy of charge transport between parallel and perpendicular to the polarization direction. The temperature-dependent evolution of Raman active in-plane 3Eg phonon, which strongly couples to the polar-active out-of-the-plane A2u phonon mode in the high-temperature paraelectric state, exhibits a deviation in Raman shift from the expectation of the pseudospin−phonon model that is widely used to model many insulating FEs. The Curie−Weiss temperature (θ ≈ 97 K) obtained from the optical susceptibility is substantially lower than Ts, suggesting a strong suppression of FE fluctuations. Both line width and Fano line shape of 3Eg Raman mode exhibit a strong electron−phonon coupling in the high-temperature paraelectric phase, which disappears in the FE phase, challenging Anderson/Blount’s proposal for the formation of FE metals.
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Ray S, Das T. Theory of angle-dependent marginal Fermi liquid self-energy and its existence at all dopings in cuprates. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:365603. [PMID: 31146268 DOI: 10.1088/1361-648x/ab25b8] [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
Various angle-dependent measurements in hole-doped cuprates suggested that non-Fermi liquid (NFL) and Fermi-liquid (FL) self-energies coexist in the Brillouin zone. Moreover, it is also found that NFL self-energies survive up to the overdoped region where the resistivity features a global FL-behavior. To address this problem, we compute the momentum dependent self-energy from a single band Hubbard model. The self-energy is calculated self-consistently by using a momentum-dependent density-fluctuation (MRDF) method. One of our main results is that the computed self-energy exhibits a marginal-FL (MFL)-like frequency dependence only in the antinodal region, and FL-like behavior elsewhere at all dopings. The MFL self-energy stems from the fluctuations between the itinerant and localized densities-a result that appears when self-energy is calculated self-consistently and features an intermediate coupling behavior of cuprates. We also calculate the DC conductivity by including the full momentum dependent self-energy. We find that the resistivity-temperature exponent n becomes 1 near the optimal doping, while the MFL self-energy occupies largest momentum-space volume. Surprisingly, even in the NFL state near the optimal doping, the nodal region contains FL-like self-energies; while in the under- and over-dopings ([Formula: see text]), the antinodal region remains NFL-like. These results highlight the non-local correlation physics in cuprates and in other similar intermediately correlated materials, where a direct link between the microscopic single-particle spectral properties and the macroscopic transport behavior can not be well established.
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Affiliation(s)
- Sujay Ray
- Department of Physics, Indian Institute of Science, Bangalore, 560012, India
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Heavy fermion quantum criticality at dilute carrier limit in CeNi 2-δ(As 1-xP x) 2. Sci Rep 2019; 9:12307. [PMID: 31444407 PMCID: PMC6707201 DOI: 10.1038/s41598-019-48662-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 08/07/2019] [Indexed: 12/03/2022] Open
Abstract
We study the quantum phase transitions in the nickel pnctides, CeNi2−δ(As1−xPx)2 (δ ≈ 0.07–0.22) polycrystalline samples. This series displays the distinct heavy fermion behavior in the rarely studied parameter regime of dilute carrier limit. We systematically investigate the magnetization, specific heat and electrical transport down to low temperatures. Upon increasing the P-content, the antiferromagnetic order of the Ce-4f moment is suppressed continuously and vanishes at xc ~ 0.55. At this doping, the temperature dependences of the specific heat and longitudinal resistivity display non-Fermi liquid behavior. Both the residual resistivity ρ0 and the Sommerfeld coefficient γ0 are sharply peaked around xc. When the P-content reaches close to 100%, we observe a clear low-temperature crossover into the Fermi liquid regime. In contrast to what happens in the parent compound x = 0.0 as a function of pressure, we find a surprising result that the non-Fermi liquid behavior persists over a nonzero range of doping concentration, xc < x < 0.9. In this doping range, at the lowest measured temperatures, the temperature dependence of the specific-heat coefficient is logarithmically divergent and that of the electrical resistivity is linear. We discuss the properties of CeNi2−δ(As1−xPx)2 in comparison with those of its 1111 counterpart, CeNi(As1−xPx)O. Our results indicate a non-Fermi liquid phase in the global phase diagram of heavy fermion metals.
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