1
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Are Heavy Fermion Strange Metals Planckian? CRYSTALS 2022; 12:251. [PMID: 35910592 PMCID: PMC8979306 DOI: 10.3390/cryst12020251] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Accepted: 02/10/2022] [Indexed: 11/22/2022]
Abstract
Strange metal behavior refers to a linear temperature dependence of the electrical resistivity that is not due to electron–phonon scattering. It is seen in numerous strongly correlated electron systems, from the heavy fermion compounds, via transition metal oxides and iron pnictides, to magic angle twisted bi-layer graphene, frequently in connection with unconventional or “high temperature” superconductivity. To achieve a unified understanding of these phenomena across the different materials classes is a central open problem in condensed matter physics. Tests whether the linear-in-temperature law might be dictated by Planckian dissipation—scattering with the rate ∼kBT/ℏ—are receiving considerable attention. Here we assess the situation for strange metal heavy fermion compounds. They allow to probe the regime of extreme correlation strength, with effective mass or Fermi velocity renormalizations in excess of three orders of magnitude. Adopting the same procedure as done in previous studies, i.e., assuming a simple Drude conductivity with the above scattering rate, we find that for these strongly renormalized quasiparticles, scattering is much weaker than Planckian, implying that the linear temperature dependence should be due to other effects. We discuss implications of this finding and point to directions for further work.
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2
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Maksimovic N, Eilbott DH, Cookmeyer T, Wan F, Rusz J, Nagarajan V, Haley SC, Maniv E, Gong A, Faubel S, Hayes IM, Bangura A, Singleton J, Palmstrom JC, Winter L, McDonald R, Jang S, Ai P, Lin Y, Ciocys S, Gobbo J, Werman Y, Oppeneer PM, Altman E, Lanzara A, Analytis JG. Evidence for a delocalization quantum phase transition without symmetry breaking in CeCoIn 5. Science 2022; 375:76-81. [PMID: 34855511 DOI: 10.1126/science.aaz4566] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The study of quantum phase transitions that are not clearly associated with broken symmetry is a major effort in condensed matter physics, particularly in regard to the problem of high-temperature superconductivity, for which such transitions are thought to underlie the mechanism of superconductivity itself. Here we argue that the putative quantum critical point in the prototypical unconventional superconductor CeCoIn5 is characterized by the delocalization of electrons in a transition that connects two Fermi surfaces of different volumes, with no apparent broken symmetry. Drawing on established theory of f-electron metals, we discuss an interpretation for such a transition that involves the fractionalization of spin and charge, a model that effectively describes the anomalous transport behavior we measured for the Hall effect.
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Affiliation(s)
- Nikola Maksimovic
- Department of Physics, University of California, Berkeley, Berkeley, CA 94720, USA.,Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Daniel H Eilbott
- Department of Physics, University of California, Berkeley, Berkeley, CA 94720, USA.,Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Tessa Cookmeyer
- Department of Physics, University of California, Berkeley, Berkeley, CA 94720, USA.,Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Fanghui Wan
- Department of Physics, University of California, Berkeley, Berkeley, CA 94720, USA.,Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Jan Rusz
- Department of Physics and Astronomy, Uppsala University, Box 516, S-75120 Uppsala, Sweden
| | - Vikram Nagarajan
- Department of Physics, University of California, Berkeley, Berkeley, CA 94720, USA.,Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Shannon C Haley
- Department of Physics, University of California, Berkeley, Berkeley, CA 94720, USA.,Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Eran Maniv
- Department of Physics, University of California, Berkeley, Berkeley, CA 94720, USA.,Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Amanda Gong
- Department of Physics, University of California, Berkeley, Berkeley, CA 94720, USA.,Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Stefano Faubel
- Department of Physics, University of California, Berkeley, Berkeley, CA 94720, USA.,Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Ian M Hayes
- Department of Physics, University of California, Berkeley, Berkeley, CA 94720, USA.,Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Ali Bangura
- National High Magnetic Field Laboratory, Tallahassee, FL 32310, USA
| | - John Singleton
- National High Magnetic Field Laboratory, Los Alamos, NM 97545, USA
| | | | - Laurel Winter
- National High Magnetic Field Laboratory, Los Alamos, NM 97545, USA
| | - Ross McDonald
- National High Magnetic Field Laboratory, Los Alamos, NM 97545, USA
| | - Sooyoung Jang
- Department of Physics, University of California, Berkeley, Berkeley, CA 94720, USA.,Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Ping Ai
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Yi Lin
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Samuel Ciocys
- Department of Physics, University of California, Berkeley, Berkeley, CA 94720, USA.,Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Jacob Gobbo
- Department of Physics, University of California, Berkeley, Berkeley, CA 94720, USA.,Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Yochai Werman
- Department of Physics, University of California, Berkeley, Berkeley, CA 94720, USA.,Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Peter M Oppeneer
- Department of Physics and Astronomy, Uppsala University, Box 516, S-75120 Uppsala, Sweden
| | - Ehud Altman
- Department of Physics, University of California, Berkeley, Berkeley, CA 94720, USA.,Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Alessandra Lanzara
- Department of Physics, University of California, Berkeley, Berkeley, CA 94720, USA.,Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - James G Analytis
- Department of Physics, University of California, Berkeley, Berkeley, CA 94720, USA.,Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
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3
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Gu Y, Liu B, Hong W, Liu Z, Zhang W, Ma X, Li S. A temperature-modulated dilatometer by using a piezobender-based device. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2020; 91:123901. [PMID: 33379959 DOI: 10.1063/5.0010826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 11/10/2020] [Indexed: 06/12/2023]
Abstract
We report a new design of a temperature-modulated dilatometer, which obtains the linear thermal expansion coefficient by measuring the oscillating changes of the sample's length and temperature by using a piezobender and a thermocouple, respectively. Using an iron-based superconductor KFe2As2 as an example, we show that this device is able to measure thin samples with high resolutions at low temperatures and high magnetic fields. Despite its incapability of giving absolute values, the new dilatometer provides a high-resolution method to study many important physical properties in condensed matter physics, such as thermal and quantum phase transitions and vortex dynamics in the superconducting state. The prototype design of this device can be further improved in many aspects to meet particular requirements.
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Affiliation(s)
- Yanhong Gu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Bo Liu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Wenshan Hong
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Zhaoyu Liu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Wenliang Zhang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Xiaoyan Ma
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Shiliang Li
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
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4
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Magnetic field-driven quantum criticality in antiferromagnetic CePtIn 4. Proc Natl Acad Sci U S A 2019; 116:20333-20338. [PMID: 31548424 DOI: 10.1073/pnas.1910293116] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Physics of the quantum critical point is one of the most perplexing topics in current condensed-matter physics. Its conclusive understanding is forestalled by the scarcity of experimental systems displaying novel aspects of quantum criticality. We present comprehensive experimental evidence of a magnetic field-tuned tricritical point separating paramagnetic, antiferromagnetic, and metamagnetic phases in the compound CePtIn4 Analyzing field variations of its magnetic susceptibility, magnetoresistance, and specific heat at very low temperatures, we trace modifications of the antiferromagnetic structure of the compound. Upon applying a magnetic field of increasing strength, the system undergoes metamagnetic transitions which persist down to the lowest temperature investigated, exhibiting first-order-like boundaries separating magnetic phases. This yields a unique phase diagram where the second-order phase transition line terminates at a tricritical point followed by 2 first-order lines reaching quantum critical end points as [Formula: see text] 0. Our findings demonstrate that CePtIn4 provides innovative perspective for studies of quantum criticality.
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5
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Mazzone DG, Gauthier N, Maimone DT, Yadav R, Bartkowiak M, Gavilano JL, Raymond S, Pomjakushin V, Casati N, Revay Z, Lapertot G, Sibille R, Kenzelmann M. Evolution of Magnetic Order from the Localized to the Itinerant Limit. PHYSICAL REVIEW LETTERS 2019; 123:097201. [PMID: 31524473 DOI: 10.1103/physrevlett.123.097201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Indexed: 06/10/2023]
Abstract
Quantum materials that feature magnetic long-range order often reveal complex phase diagrams when localized electrons become mobile. In many materials magnetism is rapidly suppressed as electronic charges dissolve into the conduction band. In materials where magnetism persists, it is unclear how the magnetic properties are affected. Here we study the evolution of the magnetic structure in Nd_{1-x}Ce_{x}CoIn_{5} from the localized to the highly itinerant limit. We observe two magnetic ground states inside a heavy-fermion phase that are detached from unconventional superconductivity. The presence of two different magnetic phases provides evidence that increasing charge delocalization affects the magnetic interactions via anisotropic band hybridization.
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Affiliation(s)
- D G Mazzone
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - N Gauthier
- Laboratory for Scientific Developments and Novel Materials, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - D T Maimone
- Laboratory for Scientific Developments and Novel Materials, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - R Yadav
- Laboratory for Scientific Developments and Novel Materials, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - M Bartkowiak
- Laboratory for Scientific Developments and Novel Materials, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - J L Gavilano
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - S Raymond
- Univ. Grenoble Alpes, CEA, IRIG, MEM, MDN, F-38000 Grenoble, France
| | - V Pomjakushin
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - N Casati
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - Z Revay
- Technische Universität München, Heinz Maier-Leibnitz Zentrum, 85747 Garching, Germany
| | - G Lapertot
- Univ. Grenoble Alpes, CEA, IRIG, PHELIQS, IMAPEC, F-38000 Grenoble, France
| | - R Sibille
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - M Kenzelmann
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
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6
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Shishido H, Yamada S, Sugii K, Shimozawa M, Yanase Y, Yamashita M. Anomalous Change in the de Haas-van Alphen Oscillations of CeCoIn_{5} at Ultralow Temperatures. PHYSICAL REVIEW LETTERS 2018; 120:177201. [PMID: 29756834 DOI: 10.1103/physrevlett.120.177201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Revised: 03/07/2018] [Indexed: 06/08/2023]
Abstract
We perform de Haas-van Alphen (dHvA) measurements of the heavy-fermion superconductor CeCoIn_{5} down to 2 mK above the upper critical field. We find that the dHvA amplitudes show an anomalous suppression, concomitantly with a shift of the dHvA frequency, below the transition temperature T_{n}=20 mK. We suggest that the change is owing to magnetic breakdown caused by a field-induced antiferromagnetic (AFM) state emerging below T_{n}, revealing the origin of the field-induced quantum critical point (QCP) in CeCoIn_{5}. The field dependence of T_{n} is found to be very weak for 7-10 T, implying that an enhancement of AFM order by suppressing the critical spin fluctuations near the AFM QCP competes with the field suppression effect on the AFM phase. We suggest that the appearance of a field-induced AFM phase is a generic feature of unconventional superconductors, which emerge near an AFM QCP, including CeCoIn_{5}, CeRhIn_{5}, and high-T_{c} cuprates.
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Affiliation(s)
- Hiroaki Shishido
- Department of Physics and Electronics, Graduate School of Engineering, Osaka Prefecture University, Sakai, Osaka 599-8531, Japan
- Institute for Nanofabrication Research, Osaka Prefecture University, Sakai, Osaka 599-8531, Japan
| | - Shogo Yamada
- The Institute for Solid State Physics, The University of Tokyo, Kashiwa 277-8581, Japan
| | - Kaori Sugii
- The Institute for Solid State Physics, The University of Tokyo, Kashiwa 277-8581, Japan
| | - Masaaki Shimozawa
- The Institute for Solid State Physics, The University of Tokyo, Kashiwa 277-8581, Japan
| | - Youichi Yanase
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
| | - Minoru Yamashita
- The Institute for Solid State Physics, The University of Tokyo, Kashiwa 277-8581, Japan
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7
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Tokiwa Y, Piening B, Jeevan HS, Bud’ko SL, Canfield PC, Gegenwart P. Super-heavy electron material as metallic refrigerant for adiabatic demagnetization cooling. SCIENCE ADVANCES 2016; 2:e1600835. [PMID: 27626073 PMCID: PMC5017822 DOI: 10.1126/sciadv.1600835] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 08/09/2016] [Indexed: 06/06/2023]
Abstract
Low-temperature refrigeration is of crucial importance in fundamental research of condensed matter physics, because the investigations of fascinating quantum phenomena, such as superconductivity, superfluidity, and quantum criticality, often require refrigeration down to very low temperatures. Currently, cryogenic refrigerators with (3)He gas are widely used for cooling below 1 K. However, usage of the gas has been increasingly difficult because of the current worldwide shortage. Therefore, it is important to consider alternative methods of refrigeration. We show that a new type of refrigerant, the super-heavy electron metal YbCo2Zn20, can be used for adiabatic demagnetization refrigeration, which does not require (3)He gas. This method has a number of advantages, including much better metallic thermal conductivity compared to the conventional insulating refrigerants. We also demonstrate that the cooling performance is optimized in Yb1-x Sc x Co2Zn20 by partial Sc substitution, with x ~ 0.19. The substitution induces chemical pressure that drives the materials to a zero-field quantum critical point. This leads to an additional enhancement of the magnetocaloric effect in low fields and low temperatures, enabling final temperatures well below 100 mK. This performance has, up to now, been restricted to insulators. For nearly a century, the same principle of using local magnetic moments has been applied for adiabatic demagnetization cooling. This study opens new possibilities of using itinerant magnetic moments for cryogen-free refrigeration.
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Affiliation(s)
- Yoshifumi Tokiwa
- I. Physikalisches Institut, Georg-August-Universität Göttingen, 37077 Göttingen, Germany
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
- Experimental Physics VI, Center for Electronic Correlations and Magnetism, University of Augsburg, 86159 Augsburg, Germany
| | - Boy Piening
- I. Physikalisches Institut, Georg-August-Universität Göttingen, 37077 Göttingen, Germany
| | - Hirale S. Jeevan
- I. Physikalisches Institut, Georg-August-Universität Göttingen, 37077 Göttingen, Germany
| | - Sergey L. Bud’ko
- Ames Laboratory, U.S. Department of Energy, and Department of Physics and Astronomy, Iowa State University, Ames, IA 50011, USA
| | - Paul C. Canfield
- Ames Laboratory, U.S. Department of Energy, and Department of Physics and Astronomy, Iowa State University, Ames, IA 50011, USA
| | - Philipp Gegenwart
- I. Physikalisches Institut, Georg-August-Universität Göttingen, 37077 Göttingen, Germany
- Experimental Physics VI, Center for Electronic Correlations and Magnetism, University of Augsburg, 86159 Augsburg, Germany
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8
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Steglich F, Wirth S. Foundations of heavy-fermion superconductivity: lattice Kondo effect and Mott physics. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2016; 79:084502. [PMID: 27376190 DOI: 10.1088/0034-4885/79/8/084502] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
This article overviews the development of heavy-fermion superconductivity, notably in such rare-earth-based intermetallic compounds which behave as Kondo-lattice systems. Heavy-fermion superconductivity is of unconventional nature in the sense that it is not mediated by electron-phonon coupling. Rather, in most cases the attractive interaction between charge carriers is apparently magnetic in origin. Fluctuations associated with an antiferromagnetic (AF) quantum critical point (QCP) play a major role. The first heavy-fermion superconductor CeCu2Si2 turned out to be the prototype of a larger group of materials for which the underlying, often pressure-induced, AF QCP is likely to be of a three-dimensional (3D) spin-density-wave (SDW) variety. For UBe13, the second heavy-fermion superconductor, a magnetic-field-induced 3D SDW QCP inside the superconducting phase can be conjectured. Such a 'conventional', itinerant QCP can be well understood within Landau's paradigm of order-parameter fluctuations. In contrast, the low-temperature normal-state properties of a few heavy-fermion superconductors are at odds with the Landau framework. They are characterized by an 'unconventional', local QCP which may be considered a zero-temperature 4 f-orbital selective Mott transition. Here, as concluded for YbRh2Si2, the breakdown of the Kondo effect concurring with the AF instability gives rise to an abrupt change of the Fermi surface. Very recently, superconductivity was discovered for this compound at ultra-low temperatures. Therefore, YbRh2Si2 along with CeRhIn5 under pressure provide a natural link between the large group of about fifty low-temperature heavy-fermion superconductors and other families of unconventional superconductors with substantially higher T c, e.g. the doped Mott insulators of the perovskite-type cuprates and the organic charge-transfer salts.
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Affiliation(s)
- Frank Steglich
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany. Center for Correlated Matter, Zhejiang University, Hangzhou, Zhejiang 310058, People's Republic of China. Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
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9
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Paglione J, Tanatar MA, Reid JP, Shakeripour H, Petrovic C, Taillefer L. Quantum Critical Quasiparticle Scattering within the Superconducting State of CeCoIn_{5}. PHYSICAL REVIEW LETTERS 2016; 117:016601. [PMID: 27419578 DOI: 10.1103/physrevlett.117.016601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Indexed: 06/06/2023]
Abstract
The thermal conductivity κ of the heavy-fermion metal CeCoIn_{5} was measured in the normal and superconducting states as a function of temperature T and magnetic field H, for a current and field parallel to the [100] direction. Inside the superconducting state, when the field is lower than the upper critical field H_{c2}, κ/T is found to increase as T→0, just as in a metal and in contrast to the behavior of all known superconductors. This is due to unpaired electrons on part of the Fermi surface, which dominate the transport above a certain field. The evolution of κ/T with field reveals that the electron-electron scattering (or transport mass m^{⋆}) of those unpaired electrons diverges as H→H_{c2} from below, in the same way that it does in the normal state as H→H_{c2} from above. This shows that the unpaired electrons sense the proximity of the field-tuned quantum critical point of CeCoIn_{5} at H^{⋆}=H_{c2} even from inside the superconducting state. The fact that the quantum critical scattering of the unpaired electrons is much weaker than the average scattering of all electrons in the normal state reveals a k-space correlation between the strength of pairing and the strength of scattering, pointing to a common mechanism, presumably antiferromagnetic fluctuations.
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Affiliation(s)
- Johnpierre Paglione
- Center for Nanophysics and Advanced Materials, Department of Physics, University of Maryland, College Park, Maryland 20742, USA
- Canadian Institute for Advanced Research, Toronto, Canada M5G 1Z8
| | - M A Tanatar
- Département de physique & RQMP, Université de Sherbrooke, Sherbrooke, Canada J1K 2R1
- Ames Laboratory USDOE and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
| | - J-Ph Reid
- Département de physique & RQMP, Université de Sherbrooke, Sherbrooke, Canada J1K 2R1
| | - H Shakeripour
- Department of Physics, Isfahan University of Technology, Isfahan 84156-83111, Iran
| | - C Petrovic
- Canadian Institute for Advanced Research, Toronto, Canada M5G 1Z8
- Department of Physics, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - Louis Taillefer
- Canadian Institute for Advanced Research, Toronto, Canada M5G 1Z8
- Département de physique & RQMP, Université de Sherbrooke, Sherbrooke, Canada J1K 2R1
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10
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Yang YF. Two-fluid model for heavy electron physics. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2016; 79:074501. [PMID: 27214153 DOI: 10.1088/0034-4885/79/7/074501] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The two-fluid model is a phenomenological description of the gradual change of the itinerant and local characters of f-electrons with temperature and other tuning parameters and has been quite successful in explaining many unusual and puzzling experimental observations in heavy electron materials. We review some of these results and discuss possible implications of the two-fluid model in understanding the microscopic origin of heavy electron physics.
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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. Collaborative Innovation Center of Quantum Matter, Beijing 100190, People's Republic of China
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11
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Tokiwa Y, Mchalwat M, Perry RS, Gegenwart P. Multiple Metamagnetic Quantum Criticality in Sr_{3}Ru_{2}O_{7}. PHYSICAL REVIEW LETTERS 2016; 116:226402. [PMID: 27314732 DOI: 10.1103/physrevlett.116.226402] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Indexed: 06/06/2023]
Abstract
Bilayer strontium ruthenate Sr_{3}Ru_{2}O_{7} displays pronounced non-Fermi liquid behavior at magnetic fields around 8 T, applied perpendicular to the ruthenate planes, which previously has been associated with an itinerant metamagnetic quantum critical end point (QCEP). We focus on the magnetic Grüneisen parameter Γ_{H}, which is the most direct probe to characterize field-induced quantum criticality. We confirm quantum critical scaling due to a putative two-dimensional QCEP near 7.845(5) T, which is masked by two ordered phases A and B, identified previously by neutron scattering. In addition, we find evidence for a QCEP at 7.53(2) T and determine the quantum critical regimes of both instabilities and the effect of their superposition.
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Affiliation(s)
- Y Tokiwa
- I. Physikalisches Institut, Georg-August-Universität Göttingen, 37077 Göttingen, Germany
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
| | - M Mchalwat
- I. Physikalisches Institut, Georg-August-Universität Göttingen, 37077 Göttingen, Germany
| | - R S Perry
- London Centre for Nanotechnology, Faculty of Maths & Physical Sciences, University College London, London-WC1E 6BT, United Kingdom
| | - P Gegenwart
- I. Physikalisches Institut, Georg-August-Universität Göttingen, 37077 Göttingen, Germany
- Experimentalphysik VI, Center for Electronic Correlations and Magnetism, Augsburg University, 86159 Augsburg, Germany
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12
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Tokiwa Y, Ishikawa JJ, Nakatsuji S, Gegenwart P. Quantum criticality in a metallic spin liquid. NATURE MATERIALS 2014; 13:356-359. [PMID: 24651428 DOI: 10.1038/nmat3900] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2013] [Accepted: 01/31/2014] [Indexed: 06/03/2023]
Abstract
When magnetic order is suppressed by frustrated interactions, spins form a highly correlated fluctuating 'spin liquid' state down to low temperatures. The magnetic order of local moments can also be suppressed when they are fully screened by conduction electrons through the Kondo effect. Thus, the combination of strong geometrical frustration and Kondo screening may lead to novel types of quantum phase transition. We report low-temperature thermodynamic measurements on the frustrated Kondo lattice Pr₂Ir₂O₇, which exhibits a chiral spin liquid state below 1.5 K as a result of the frustrated interaction between Ising 4f local moments and their interplay with Ir conduction electrons. Our results provide a first clear example of zero-field quantum critical scaling that emerges in a spin liquid state of a highly frustrated metal.
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