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Nodal quasiparticle dynamics in the heavy fermion superconductor CeCoIn₅ revealed by precision microwave spectroscopy. Nat Commun 2014; 4:2477. [PMID: 24051545 DOI: 10.1038/ncomms3477] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Accepted: 08/21/2013] [Indexed: 11/08/2022] Open
Abstract
CeCoIn₅ is a heavy fermion superconductor with strong similarities to the high-Tc cuprates, including quasi-two-dimensionality, proximity to antiferromagnetism and probable d-wave pairing arising from a non-Fermi-liquid normal state. Experiments allowing detailed comparisons of their electronic properties are of particular interest, but in most cases are difficult to realize, due to their very different transition temperatures. Here we use low-temperature microwave spectroscopy to study the charge dynamics of the CeCoIn₅ superconducting state. The similarities to cuprates, in particular to ultra-clean YBa₂Cu₃O(y), are striking: the frequency and temperature dependence of the quasiparticle conductivity are instantly recognizable, a consequence of rapid suppression of quasiparticle scattering below T(c); and penetration-depth data, when properly treated, reveal a clean, linear temperature dependence of the quasiparticle contribution to superfluid density. The measurements also expose key differences, including prominent multiband effects and a temperature-dependent renormalization of the quasiparticle mass.
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Luetkens H, Klauss HH, Khasanov R, Amato A, Klingeler R, Hellmann I, Leps N, Kondrat A, Hess C, Köhler A, Behr G, Werner J, Büchner B. Field and temperature dependence of the superfluid density in LaFeAsO1-xFx superconductors: a muon spin relaxation study. PHYSICAL REVIEW LETTERS 2008; 101:097009. [PMID: 18851647 DOI: 10.1103/physrevlett.101.097009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2008] [Indexed: 05/26/2023]
Abstract
We present zero field and transverse field muon spin relaxation experiments on the recently discovered Fe-based superconductor LaFeAsO1-xFx (x=0.075 and x=0.1). The temperature dependence of the deduced superfluid density is consistent with a BCS s-wave or a dirty d-wave gap function, while the field dependence strongly evidences unconventional superconductivity. We obtain the in-plane penetration depth of lambda ab(0)=254(2) nm for x=0.1 and lambda ab(0)=364(8) nm for x=0.075. Further evidence for unconventional superconductivity is provided by the ratio of Tc versus the superfluid density, which is close to the Uemura line of high-Tc cuprates.
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Affiliation(s)
- H Luetkens
- Laboratory for Muon-Spin Spectroscopy, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland.
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Broun DM, Huttema WA, Turner PJ, Ozcan S, Morgan B, Liang R, Hardy WN, Bonn DA. Superfluid density in a highly underdoped YBa_{2}Cu_{3}O_{6+y} superconductor. PHYSICAL REVIEW LETTERS 2007; 99:237003. [PMID: 18233402 DOI: 10.1103/physrevlett.99.237003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2007] [Indexed: 05/25/2023]
Abstract
The superfluid density rho_{s}(T) identical with1/lambda;{2}(T) has been measured at 2.64 GHz in highly underdoped YBa_{2}Cu_{3}O_{6+y}, at 37 dopings with T_{c} between 3 and 17 K. Within limits set by the transition width DeltaT_{c} approximately 0.4 K, rho_{s}(T) shows no evidence of critical fluctuations as T-->T_{c}, with a mean-field-like transition and no indication of vortex unbinding. Instead, we propose that rho_{s} displays the behavior expected for a quantum phase transition in the (3+1)-dimensional XY universality class, with rho_{s0} proportional, variant(p-p_{c}), T_{c} proportional, variant(p-p_{c});{1/2}, and rho_{s}(T) proportional, variant(T_{c}-T);{1} as T-->T_{c}.
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Affiliation(s)
- D M Broun
- Department of Physics, Simon Fraser University, Burnaby, British Columbia, Canada V5A 1S6
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Gusynin VP, Sharapov SG, Carbotte JP. Unusual microwave response of dirac quasiparticles in graphene. PHYSICAL REVIEW LETTERS 2006; 96:256802. [PMID: 16907333 DOI: 10.1103/physrevlett.96.256802] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2006] [Indexed: 05/06/2023]
Abstract
Recent experiments have proven that the quasiparticles in graphene obey a Dirac equation. Here we show that microwaves are an excellent probe of their unusual dynamics. When the chemical potential is small, the intraband response can exhibit a cusp around zero frequency Omega and this unusual line shape changes to Drude-like by increasing the chemical potential |mu|, with width linear in mu. The interband contribution at T=0 is a constant independent of Omega with a lower cutoff at 2mu. Distinctly different behavior occurs if interaction-induced phenomena in graphene cause an opening of a gap Delta. At a large magnetic field B, the diagonal and Hall conductivities at small Omega become independent of B but remain nonzero and show a structure associated with the lowest Landau level. This occurs because in the Dirac theory the energy of this level, E0 = +/-Delta, is field independent in sharp contrast to the conventional case.
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Affiliation(s)
- V P Gusynin
- Bogolyubov Institute for Theoretical Physics, Metrologicheskaya Street 14-b, Kiev, 03143, Ukraine
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Jin BB, Dahm T, Gubin AI, Choi EM, Kim HJ, Lee SI, Kang WN, Klein N. Anomalous coherence peak in the microwave conductivity of c-axis oriented MgB2 thin films. PHYSICAL REVIEW LETTERS 2003; 91:127006. [PMID: 14525394 DOI: 10.1103/physrevlett.91.127006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2003] [Indexed: 05/24/2023]
Abstract
The temperature dependence of the real part of the microwave complex conductivity at 17.9 GHz obtained from surface impedance measurements of two c-axis oriented MgB2 thin films reveals a pronounced maximum at a temperature around 0.6 times the critical temperature. Calculations in the frame of a two-band model based on Bardeen-Cooper-Schrieffer (BCS) theory suggest that this maximum corresponds to an anomalous coherence peak resembling the two-gap nature of MgB2. Our model assumes there is no interband impurity scattering and a weak interband pairing interaction, as suggested by band structure calculations. In addition, the observation of a coherence peak indicates that the pi band is in the dirty limit and dominates the total conductivity of our films.
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Affiliation(s)
- B B Jin
- Forschungszentrum Jülich GmbH, Institute of Thin Films and Interfaces, D-52425 Jülich, Germany
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Turner PJ, Harris R, Kamal S, Hayden ME, Broun DM, Morgan DC, Hosseini A, Dosanjh P, Mullins GK, Preston JS, Liang R, Bonn DA, Hardy WN. Observation of weak-limit quasiparticle scattering via broadband microwave spectroscopy of a d-wave superconductor. PHYSICAL REVIEW LETTERS 2003; 90:237005. [PMID: 12857284 DOI: 10.1103/physrevlett.90.237005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2002] [Indexed: 05/24/2023]
Abstract
There has long been a discrepancy between microwave conductivity measurements in high temperature superconductors and the conductivity spectrum expected in the simplest models for impurity scattering in a d-wave superconductor. Here we present a new type of broadband measurement of microwave surface resistance that finally shows some of the spectral features expected for a d(x2-y2) pairing state. Cusp-shaped conductivity spectra, consistent with weak impurity scattering of nodal quasiparticles, were obtained in the 0.6-21 GHz frequency range in highly ordered crystals of YBa2Cu3O6.50 and YBa2Cu3O6.99.
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Affiliation(s)
- P J Turner
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z1
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Iyengar A, Stajic J, Kao YJ, Levin K. ab plane ac conductivity in the cuprates: pseudogap effects below Tc. PHYSICAL REVIEW LETTERS 2003; 90:187003. [PMID: 12786038 DOI: 10.1103/physrevlett.90.187003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2002] [Indexed: 05/24/2023]
Abstract
Building on our understanding of the superfluid density rho(s)(T), we show how the pseudogap enters the in-plane optical conductivity sigma(omega,T) for temperatures T</=T(c). Signatures in sigma(omega,T) associated with competing proposals of a "hidden order" and "superconducting" origin for the pseudogap differ in their qualitative omega,T dependences. For the latter case, as T increases from 0, Re sigma(omega) is enhanced at high and low frequencies. We discuss these theories in light of current experiments.
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Affiliation(s)
- Andrew Iyengar
- James Franck Institute, University of Chicago, Chicago, Illinois 60637, USA
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Abstract
The high-temperature copper oxide superconductors are of fundamental and enduring interest. They not only manifest superconducting transition temperatures inconceivable 15 years ago, but also exhibit many other properties apparently incompatible with conventional metal physics. The materials expand our notions of what is possible, and compel us to develop new experimental techniques and theoretical concepts. This article provides a perspective on recent developments and their implications for our understanding of interacting electrons in metals.
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Affiliation(s)
- J Orenstein
- Department of Physics, University of California, Berkeley, CA 94720, USA, and Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA. Department of Physics and Astronomy, Rutgers University, Piscataway, NJ
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Buan J, Stojkovic BP, Israeloff N, Goldman AM, Huang CC, Valls OT, Jacobs T, Sridhar S, Shih CR, Yang HD, Liu JZ, Shelton R. Experimental investigation of the pairing state of high-temperature superconductors. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 54:7462-7469. [PMID: 9984373 DOI: 10.1103/physrevb.54.7462] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Shafranjuk SE, Tachiki M, Yamashita T. ac properties of an anisotropic layered superconductor. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 53:15136-15146. [PMID: 9983312 DOI: 10.1103/physrevb.53.15136] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Bonn DA, Kamal S, Bonakdarpour A, Liang R, Hardy WN, Homes CC, Basov DN, Timusk T. Surface impedance studies of YBCO. ACTA ACUST UNITED AC 1996. [DOI: 10.1007/bf02548130] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Graf MJ, Yip SK, Sauls JA, Rainer D. Electronic thermal conductivity and the Wiedemann-Franz law for unconventional superconductors. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 53:15147-15161. [PMID: 9983313 DOI: 10.1103/physrevb.53.15147] [Citation(s) in RCA: 93] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Quinlan SM, Hirschfeld PJ, Scalapino DJ. Infrared conductivity of a dx2-y2-wave superconductor with impurity and spin-fluctuation scattering. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 53:8575-8582. [PMID: 9982366 DOI: 10.1103/physrevb.53.8575] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Ziegler W, Poilblanc D, Preuss R, Hanke W, Scalapino DJ. T-matrix formulation of impurity scattering in correlated systems. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 53:8704-8707. [PMID: 9982384 DOI: 10.1103/physrevb.53.8704] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Palumbo M, Graf MJ. Electromagnetic absorption in an anisotropic layered superconductor. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 53:2261-2264. [PMID: 9983725 DOI: 10.1103/physrevb.53.2261] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Halbritter J. Granular superconductors and their intrinsic and extrinsic surface impedance. ACTA ACUST UNITED AC 1995. [DOI: 10.1007/bf00727492] [Citation(s) in RCA: 119] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Graf MJ, Palumbo M, Rainer D, Sauls JA. Infrared conductivity in layered d-wave superconductors. PHYSICAL REVIEW. B, CONDENSED MATTER 1995; 52:10588-10600. [PMID: 9980112 DOI: 10.1103/physrevb.52.10588] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Titov ML, Yashenkin AG, Aristov DN. Quasiparticle damping in two-dimensional superconductors with unconventional pairing. PHYSICAL REVIEW. B, CONDENSED MATTER 1995; 52:10626-10632. [PMID: 9980116 DOI: 10.1103/physrevb.52.10626] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Borkowski LS, Hirschfeld PJ, Putikka WO. Transport properties of extended-s-state superconductors. PHYSICAL REVIEW. B, CONDENSED MATTER 1995; 52:R3856-R3859. [PMID: 9981611 DOI: 10.1103/physrevb.52.r3856] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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