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Ienaga K, Tamoto Y, Yoda M, Yoshimura Y, Ishigami T, Okuma S. Broadened quantum critical ground state in a disordered superconducting thin film. Nat Commun 2024; 15:2388. [PMID: 38493176 PMCID: PMC10944498 DOI: 10.1038/s41467-024-46628-7] [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: 08/25/2023] [Accepted: 02/29/2024] [Indexed: 03/18/2024] Open
Abstract
A superconductor-insulator transition (SIT) in two dimensions is a prototypical quantum phase transition (QPT) with a clear quantum critical point (QCP) at zero temperature (T = 0). The SIT is induced by a field B and observed in disordered thin films. In some of weakly disordered or crystalline thin films, however, an anomalous metallic (AM) ground state emerges over a wide B range between the superconducting and insulating phases. It remains a fundamental open question how the QPT picture of the SIT is modified when the AM state appears. Here we present measurements of the Nernst effect N, which has great sensitivity to the fluctuations of the superconducting order parameter. From a thorough contour map of N in the B-T plane, we found a thermal-to-quantum crossover line of the superconducting fluctuations, a so-called ghost-temperature line associated with the QPT, as well as a ghost-field line associated with a thermal transition. The QCP is identified as a T = 0 intercept of the ghost-temperature line inside the AM state, which verifies that the AM state is a broadened critical state of the SIT.
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Affiliation(s)
- Koichiro Ienaga
- Department of Physics, Tokyo Institute of Technology, 2-12-1 Ohokayama, Meguro-ku, Tokyo, 152-8551, Japan.
| | - Yutaka Tamoto
- Department of Physics, Tokyo Institute of Technology, 2-12-1 Ohokayama, Meguro-ku, Tokyo, 152-8551, Japan
| | - Masahiro Yoda
- Department of Physics, Tokyo Institute of Technology, 2-12-1 Ohokayama, Meguro-ku, Tokyo, 152-8551, Japan
| | - Yuki Yoshimura
- Department of Physics, Tokyo Institute of Technology, 2-12-1 Ohokayama, Meguro-ku, Tokyo, 152-8551, Japan
| | - Takahiro Ishigami
- Department of Physics, Tokyo Institute of Technology, 2-12-1 Ohokayama, Meguro-ku, Tokyo, 152-8551, Japan
| | - Satoshi Okuma
- Department of Physics, Tokyo Institute of Technology, 2-12-1 Ohokayama, Meguro-ku, Tokyo, 152-8551, Japan
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Behnia K. Nernst response, viscosity and mobile entropy in vortex liquids. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 35:074003. [PMID: 36541498 DOI: 10.1088/1361-648x/aca9b0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 12/07/2022] [Indexed: 06/17/2023]
Abstract
In a liquid of superconducting vortices, a longitudinal thermal gradient generates a transverse electric field. This Nernst signal peaks at an intermediate temperature and magnetic field, presumably where the entropy difference between the vortex core and the superfluid environment is largest. There is a puzzling similarity of the amplitude of this peak across many different superconductors. This peak can be assimilated to a minimum in the viscosity to entropy density ratio of the vortex liquid. Expressed in units ofℏkB, this minimum is one order of magnitude larger than what is seen in common liquids. Moreover, the entropy stocked in the vortex core isnotidentical to the entropy bound to a moving magnetic flux line. Due to a steady exchange of normal quasi-particles, entropy can leak from the vortex core. A slowly moving vortex will be peeled off its entropy within a distance of the order of a superconducting coherence length, provided that theΔEFratio is sufficiently large.
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Affiliation(s)
- Kamran Behnia
- Laboratoire de Physique et Etude des Matériaux (CNRS- Sorbonne Université), ESPCI Paris, PSL University, 75005 Paris, France
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3
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Llovo IF, Mosqueira J, Carballeira C, Vidal F. Precursor superconducting effects in the optimally doped YBa2Cu3O7−δ superconductor: the confrontation between superconducting fluctuations and percolative effects revisited. SN APPLIED SCIENCES 2022. [DOI: 10.1007/s42452-022-04995-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Abstract
AbstractThe confrontation between the superconducting fluctuations and percolation effects as the origin of the in-plane paraconductivity in cuprate superconductors was earlier addressed at a quantitative level in the case of the optimally doped YBa2Cu3O7−δ (YBCO) compound. Using in-plane resistivity data from a high-quality YBCO thin film, we will extend these analyses to high reduced temperatures, in the case of the Gaussian-Ginzburg–Landau (GGL) approach for the conventional superconducting fluctuations, by considering the total energy cutoff. These data will also be analysed in terms of the mean field-approach of the effective-medium theory, to probe if emergent percolative effects may account for the resistivity rounding above $$T_{c}$$
T
c
. Our analyses confirm earlier conclusions: the measured paraconductivity cannot be explained in terms of emergent percolation processes, but it may be accounted for in terms of the GGL approach. These results also call into question alternative scenarios, including a recent proposal derived from emergent percolative effects.
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Rischau CW, Li Y, Fauqué B, Inoue H, Kim M, Bell C, Hwang HY, Kapitulnik A, Behnia K. Universal Bound to the Amplitude of the Vortex Nernst Signal in Superconductors. PHYSICAL REVIEW LETTERS 2021; 126:077001. [PMID: 33666461 DOI: 10.1103/physrevlett.126.077001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 11/05/2020] [Accepted: 01/07/2021] [Indexed: 06/12/2023]
Abstract
A liquid of superconducting vortices generates a transverse thermoelectric response. This Nernst signal has a tail deep in the normal state due to superconducting fluctuations. Here, we present a study of the Nernst effect in two-dimensional heterostructures of Nb-doped strontium titanate (STO) and in amorphous MoGe. The Nernst signal generated by ephemeral Cooper pairs above the critical temperature has the magnitude expected by theory in STO. On the other hand, the peak amplitude of the vortex Nernst signal below T_{c} is comparable in both and in numerous other superconductors despite the large distribution of the critical temperature and the critical magnetic fields. In four superconductors belonging to different families, the maximum Nernst signal corresponds to an entropy per vortex per layer of ≈k_{B}ln2.
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Affiliation(s)
- Carl Willem Rischau
- Laboratoire de Physique et d'Étude des Matériaux (ESPCI Paris-CNRS-Sorbonne Université), PSL Research University, 75005 Paris, France
| | - Yuke Li
- Laboratoire de Physique et d'Étude des Matériaux (ESPCI Paris-CNRS-Sorbonne Université), PSL Research University, 75005 Paris, France
| | - Benoît Fauqué
- JEIP, USR 3573 CNRS, Collège de France, PSL Research University, 75005 Paris, France
| | - Hisashi Inoue
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305, USA
| | - Minu Kim
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305, USA
| | - Christopher Bell
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305, USA
| | - Harold Y Hwang
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305, USA
| | - Aharon Kapitulnik
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305, USA
| | - Kamran Behnia
- Laboratoire de Physique et d'Étude des Matériaux (ESPCI Paris-CNRS-Sorbonne Université), PSL Research University, 75005 Paris, France
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Ienaga K, Hayashi T, Tamoto Y, Kaneko S, Okuma S. Quantum Criticality inside the Anomalous Metallic State of a Disordered Superconducting Thin Film. PHYSICAL REVIEW LETTERS 2020; 125:257001. [PMID: 33416373 DOI: 10.1103/physrevlett.125.257001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 11/10/2020] [Indexed: 06/12/2023]
Abstract
The field-induced superconductor-insulator transition (SIT) in two-dimensional (2D) systems is a famous example of a quantum phase transition. However, an emergence of an anomalous metallic state induced by field has been a long-standing problem in 2D superconductors. While theories predicted that the emergence is attributed to strong phase fluctuations of the superconducting order parameter due to quantum fluctuations, usual resistance measurements have not probed them directly. Here, using Nernst effect measurements, we uncover superconducting fluctuations in the vicinity of the field-induced metallic state in an amorphous Mo_{x}Ge_{1-x} thin film. The field range where the vortex Nernst signals are detectable remains nonzero toward zero temperature, and it locates inside the metallic state defined by the magnetoresistance, indicating that the metallic state results from quantum vortex liquid (QVL) with phase fluctuations due to quantum fluctuations. Slow decay of transport entropy of vortices in the QVL with decreasing temperature suggests that the metallic state originates from broadening of a quantum critical point in SIT.
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Affiliation(s)
- K Ienaga
- Department of Physics, Tokyo Institute of Technology, 2-12-1 Ohokayama, Meguro-ku, Tokyo 152-8551, Japan
| | - T Hayashi
- Department of Physics, Tokyo Institute of Technology, 2-12-1 Ohokayama, Meguro-ku, Tokyo 152-8551, Japan
| | - Y Tamoto
- Department of Physics, Tokyo Institute of Technology, 2-12-1 Ohokayama, Meguro-ku, Tokyo 152-8551, Japan
| | - S Kaneko
- Department of Physics, Tokyo Institute of Technology, 2-12-1 Ohokayama, Meguro-ku, Tokyo 152-8551, Japan
| | - S Okuma
- Department of Physics, Tokyo Institute of Technology, 2-12-1 Ohokayama, Meguro-ku, Tokyo 152-8551, Japan
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Kavokin AV, Galperin YM, Varlamov AA. Proposed Model of the Giant Thermal Hall Effect in Two-Dimensional Superconductors: An Extension to the Superconducting Fluctuation Regime. PHYSICAL REVIEW LETTERS 2020; 125:217005. [PMID: 33274986 DOI: 10.1103/physrevlett.125.217005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 08/26/2020] [Accepted: 10/23/2020] [Indexed: 06/12/2023]
Abstract
We extend the thermodynamic approach for the description of the thermal Hall effect in two-dimensional superconductors above the critical temperature, where fluctuation Cooper pairs contribute to the conductivity, as well as in disordered normal metals where the particle-particle channel is important. We express the Hall heat conductivity in terms of the product of temperature derivatives of the chemical potential and of the magnetization of the system. Based on this general expression, we derive the analytical formalism that qualitatively reproduces the superlinear increase of the thermal Hall conductivity with the decrease of temperature observed in a large variety of experimentally studied systems [Grissonnanche et al., Nature (London) 571, 376 (2019)NATUAS0028-083610.1038/s41586-019-1375-0]. We also predict a nonmonotonic behavior of the thermal Hall conductivity in the regime of quantum fluctuations, in the vicinity of the second critical field and at very low temperatures.
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Affiliation(s)
- A V Kavokin
- Westlake University, 18 Shilongshan Road, Hangzhou 310024, Zhejiang Province, China
- Institute of Natural Sciences, Westlake Institute for Advanced Study, 18 Shilongshan Road, Hangzhou 310024, Zhejiang Province, China
- Spin Optics Laboratory, St. Petersburg State University, Ulyanovskaya 1, 198504 St. Petersburg, Russia
| | - Y M Galperin
- A. F. Ioffe Physico-Technical Institute of Russian Academy of Sciences, Polytekhnicheskaya 26, 194021 St. Petersburg, Russia
- Department of Physics, University of Oslo, 0316 Oslo, Norway
| | - A A Varlamov
- CNR-SPIN, DICII-University of Rome Tor Vergata, Via del Politecnico 1, 00133 Rome, Italy
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Kavokin AV, Altshuler BL, Sharapov SG, Grigoryev PS, Varlamov AA. The Nernst effect in Corbino geometry. Proc Natl Acad Sci U S A 2020; 117:2846-2851. [PMID: 31992642 PMCID: PMC7022160 DOI: 10.1073/pnas.1916567117] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We study the manifestation of the Nernst effect in the Corbino disk subjected to the normal external magnetic field and to the radial temperature gradient. The Corbino geometry offers a precious opportunity for the direct measurement of the magnetization currents that are masked by kinetic contributions to the Nernst current in the conventional geometry. The magnetization currents, also referred to as the edge currents, are independent on the conductivity of the sample which is why they can be conveniently described within the thermodynamic approach. They can be related to the Landau thermodynamic potential for an infinite system. We demonstrate that the observable manifestation of this, purely thermodynamic, Nernst effect consists in the strong oscillations of the magnetic field measured in the center of the disk as a function of the external field. The oscillations depend on the temperature difference at the edges of the disk. Dirac fermions and 2D electrons with a parabolic spectrum are characterized by oscillations of different phase and frequency. We predict qualitatively different power dependencies of the magnitude of the Nernst signal on the chemical potential for normal and Dirac carriers.
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Affiliation(s)
- A V Kavokin
- Westlake University, Hangzhou 310024, Zhejiang Province, China;
| | - B L Altshuler
- Westlake University, Hangzhou 310024, Zhejiang Province, China;
- Department of Physics, Columbia University, New York, NY 10027
| | - S G Sharapov
- Bogolyubov Institute for Theoretical Physics, National Academy of Science of Ukraine, Kyiv 03680, Ukraine
| | - P S Grigoryev
- Spin Optics Laboratory, St. Petersburg State University, 198504 St. Petersburg, Russia
| | - A A Varlamov
- Consiglio Nazionale delle Ricerche-Superconducting and Other Innovative Materials and Devices Institute (CNR-SPIN), DICII-Universitá di Roma Tor Vergata, I-00133 Roma, Italy
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Xiao H, Gao B, Ma YH, Li XJ, Mu G, Hu T. Superconducting fluctuation effect in CaFe0.88Co0.12AsF. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2016; 28:455701. [PMID: 27619794 DOI: 10.1088/0953-8984/28/45/455701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Out-of-plane angular dependent torque measurements were performed on CaFe0.88Co0.12AsF single crystals. Superconducting fluctuations, featured by magnetic field enhanced and exponential temperature dependent diamagnetism, are observed above the superconducting transition temperature T c, which is similar to that of cuprate superconductors, but less pronounced. In addition, the ratio of T c versus superfluid density follows well the Uemura line of high-T c cuprates, which suggests the exotic nature of the superconductivity in CaFe0.88Co0.12AsF.
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Affiliation(s)
- H Xiao
- Center for High Pressure Science and Technology Advanced Research, Beijing, 100094, People's Republic of China
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Behnia K, Aubin H. Nernst effect in metals and superconductors: a review of concepts and experiments. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2016; 79:046502. [PMID: 27010481 DOI: 10.1088/0034-4885/79/4/046502] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The Nernst effect is the transverse electric field produced by a longitudinal thermal gradient in the presence of a magnetic field. At the beginning of this century, Nernst experiments on cuprates were analyzed assuming that: (i) the contribution of quasi-particles to the Nernst signal is negligible; and (ii) Gaussian superconducting fluctuations cannot produce a Nernst signal well above the critical temperature. Both these assumptions were contradicted by subsequent experiments. This paper reviews experiments documenting multiple sources of a Nernst signal, which, according to the Bridgman relation, measures the flow of transverse entropy caused by a longitudinal particle flow. Along the lines of Landauer's approach to transport phenomena, the magnitude of the transverse magneto-thermoelectric response is linked to the quantum of thermoelectric conductance and a number of material-dependent length scales: the mean free path, the Fermi wavelength, the de Broglie thermal wavelength and the superconducting coherence length. Extremely mobile quasi-particles in dilute metals generate a widely-documented Nernst signal. Fluctuating Cooper pairs in the normal state of superconductors have been found to produce a detectable Nernst signal with an amplitude conforming to the Gaussian theory, first conceived by Ussishkin, Sondhi and Huse. In addition to these microscopic sources, mobile Abrikosov vortices, mesoscopic objects simultaneously carrying entropy and magnetic flux, can produce a sizeable Nernst response. Finally, in metals subject to a magnetic field strong enough to truncate the Fermi surface to a few Landau tubes, each exiting tube generates a peak in the Nernst response. The survey of these well-established sources of the Nernst signal is a helpful guide to identify the origin of the Nernst signal in other controversial cases.
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Affiliation(s)
- Kamran Behnia
- Laboratoire de Physique et d'Etude des Matériaux, (Centre National de la Recherche Scientifique-Université Pierre et Marie Curie), Ecole Supérieure de Physique et de Chimie Industrielles, 75005 Paris, France
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10
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Resonant tunneling of fluctuation Cooper pairs. Sci Rep 2015; 5:8315. [PMID: 25661237 PMCID: PMC4321188 DOI: 10.1038/srep08315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Accepted: 01/13/2015] [Indexed: 12/03/2022] Open
Abstract
Superconducting fluctuations have proved to be an irreplaceable source of information about microscopic and macroscopic material parameters that could be inferred from the experiment. According to common wisdom, the effect of thermodynamic fluctuations in the vicinity of the superconducting transition temperature, Tc, is to round off all of the sharp corners and discontinuities, which otherwise would have been expected to occur at Tc. Here we report the current spikes due to radiation-induced resonant tunneling of fluctuation Cooper pairs between two superconductors which grow even sharper and more pronounced upon approach to Tc. This striking effect offers an unprecedented tool for direct measurements of fluctuation Cooper pair lifetime, which is key to our understanding of the fluctuation regime, most notably to nature of the pseudogap state in high-temperature superconductors. Our finding marks a radical departure from the conventional view of superconducting fluctuations as a blurring and rounding phenomenon.
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Nam MS, Mézière C, Batail P, Zorina L, Simonov S, Ardavan A. Superconducting fluctuations in organic molecular metals enhanced by Mott criticality. Sci Rep 2013; 3:3390. [PMID: 24292063 PMCID: PMC3844941 DOI: 10.1038/srep03390] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2013] [Accepted: 11/11/2013] [Indexed: 11/09/2022] Open
Abstract
Unconventional superconductivity typically occurs in materials in which a small change of a parameter such as bandwidth or doping leads to antiferromagnetic or Mott insulating phases. As such competing phases are approached, the properties of the superconductor often become increasingly exotic. For example, in organic superconductors and underdoped high-Tc cuprate superconductors a fluctuating superconducting state persists to temperatures significantly above Tc. By studying alloys of quasi-two-dimensional organic molecular metals in the κ-(BEDT-TTF)2X family, we reveal how the Nernst effect, a sensitive probe of superconducting phase fluctuations, evolves in the regime of extreme Mott criticality. We find strong evidence that, as the phase diagram is traversed through superconductivity towards the Mott state, the temperature scale for superconducting fluctuations increases dramatically, eventually approaching the temperature at which quasiparticles become identifiable at all.
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Affiliation(s)
- Moon-Sun Nam
- Clarendon Laboratory, Department of Physics, University of Oxford, OX1 3PU, UK
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Luk'yanchuk IA, Varlamov AA, Kavokin AV. Giant Nernst-Ettingshausen oscillations in semiclassically strong magnetic fields. PHYSICAL REVIEW LETTERS 2011; 107:016601. [PMID: 21797559 DOI: 10.1103/physrevlett.107.016601] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2010] [Indexed: 05/31/2023]
Abstract
We consider the Nernst-Ettingshausen (NE) effect in the presence of semiclassically strong magnetic fields for a quasi-two-dimensional system with a parabolic or linear dispersion of carriers. We show that the occurring giant oscillations of the NE coefficient are coherent with the recent experimental observation in graphene, graphite, and bismuth. In the 2D case we find the exact shape of these oscillations and show that their magnitude decreases (increases) with enhancement of the Fermi energy for Dirac fermions (normal carriers). With a crossover to the 3D spectrum the phase of the oscillations shifts, their amplitude decreases, and the peaks become asymmetric.
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Affiliation(s)
- Igor A Luk'yanchuk
- Laboratory of Condensed Matter Physics, University of Picardie Jules Verne, Amiens, France
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Sergeev A, Reizer M, Mitin V. Comment on "Giant Nernst effect due to fluctuating Cooper pairs in superconductors". PHYSICAL REVIEW LETTERS 2011; 106:139701-139702. [PMID: 21517431 DOI: 10.1103/physrevlett.106.139701] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2009] [Revised: 05/06/2010] [Indexed: 05/30/2023]
Affiliation(s)
- A Sergeev
- SUNY at Buffalo, Buffalo, New York 14260, USA
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Kotetes P, Varelogiannis G. Chirality induced tilted-hill giant Nernst signal. PHYSICAL REVIEW LETTERS 2010; 104:106404. [PMID: 20366442 DOI: 10.1103/physrevlett.104.106404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2009] [Indexed: 05/29/2023]
Abstract
We reveal a novel source of a giant Nernst response exhibiting strong nonlinear temperature and magnetic field dependence, including the mysterious tilted-hill temperature profile observed in a pleiad of materials. The phenomenon results directly from the formation of a chiral ground state, e.g., a chiral d-density wave, which is compatible with the eventual observation of diamagnetism and is distinctly different from the usual quasiparticle and vortex Nernst mechanisms. Our picture provides a unified understanding of the anomalous thermoelectricity observed in materials as diverse as the hole-doped cuprates and heavy-fermion compounds like URu(2)Si(2).
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Affiliation(s)
- P Kotetes
- Department of Physics, National Technical University of Athens, GR-15780 Athens, Greece.
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Tewari S, Zhang C. Effects of quasiparticle ambipolarity on the nernst effect in underdoped cuprate superconductors. PHYSICAL REVIEW LETTERS 2009; 103:077001. [PMID: 19792675 DOI: 10.1103/physrevlett.103.077001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2009] [Indexed: 05/28/2023]
Abstract
We consider the Nernst effect in the normal state of the underdoped cuprate superconductors, where recent quantum oscillation experiments have indicated the existence of Fermi surface pockets and quasiparticle ambipolarity in the excitation spectrum. Using an ambipolar d-density-wave model for the pseudogap, we predict a peak in the Nernst coefficient with decreasing temperature below the pseudogap temperature. The existence of the peak and its sign, which we predict to be the same as that due to mobile vortices in a superconductor, result from the dominance of the electron pocket at low temperatures, as has been observed in recent Hall experiments.
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Affiliation(s)
- Sumanta Tewari
- Department of Physics and Astronomy, Clemson University, Clemson, South Carolina 29634, USA
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