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Wårdh J, Granath M, Wu J, Bollinger AT, He X, Božović I. Colossal transverse magnetoresistance due to nematic superconducting phase fluctuations in a copper oxide. PNAS Nexus 2023; 2:pgad255. [PMID: 37601309 PMCID: PMC10438889 DOI: 10.1093/pnasnexus/pgad255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Accepted: 07/25/2023] [Indexed: 08/22/2023]
Abstract
Electronic anisotropy ("nematicity") has been detected in cuprate superconductors by various experimental techniques. Using angle-resolved transverse resistance (ARTR) measurements, a very sensitive and background-free technique that can detect 0.5% anisotropy in transport, we have observed it also in La2-xSrxCuO4 (LSCO) for 0.02 ≤ x ≤ 0.25. A central enigma in LSCO is the rotation of the nematic director (orientation of the largest longitudinal resistance) with temperature; this has not been seen before in any material. Here, we address this puzzle by measuring the angle-resolved transverse magnetoresistance (ARTMR) in LSCO. We report the discovery of colossal transverse magnetoresistance (CTMR)-an order-of-magnitude drop in the transverse resistivity in the magnetic field of 6 T. We show that the apparent rotation of the nematic director is caused by anisotropic superconducting fluctuations, which are not aligned with the normal electron fluid, consistent with coexisting bond-aligned and diagonal nematic orders. We quantify this by modeling the (magneto-)conductivity as a sum of normal (Drude) and paraconducting (Aslamazov-Larkin) channels but extended to contain anisotropic Drude and Cooper-pair effective mass tensors. Strikingly, the anisotropy of Cooper-pair stiffness is much larger than that of the normal electrons. It grows dramatically on the underdoped side, where the fluctuations become quasi-one-dimensional. Our analysis is general rather than model dependent. Still, we discuss some candidate microscopic models, including coupled strongly-correlated ladders where the transverse (interladder) phase stiffness is low compared with the longitudinal intraladder stiffness, as well as the anisotropic superconducting fluctuations expected close to the transition to a pair-density wave state.
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Affiliation(s)
- Jonatan Wårdh
- Department of Physics, University of Gothenburg, SE-41296 Gothenburg, Sweden
| | - Mats Granath
- Department of Physics, University of Gothenburg, SE-41296 Gothenburg, Sweden
| | - Jie Wu
- Brookhaven National Laboratory, Upton, NY 11973, USA
- Present address: School of Science, Westlake University, Hangzhou, China
| | | | - Xi He
- Department of Chemistry, Yale University, New Haven, CT 06520, USA
- Energy Sciences Institute, Yale University, West Haven, CT 06516, USA
| | - Ivan Božović
- Brookhaven National Laboratory, Upton, NY 11973, USA
- Department of Chemistry, Yale University, New Haven, CT 06520, USA
- Energy Sciences Institute, Yale University, West Haven, CT 06516, USA
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Berg E, Chen CC, Kivelson SA. Stability of nodal quasiparticles in superconductors with coexisting orders. Phys Rev Lett 2008; 100:027003. [PMID: 18232911 DOI: 10.1103/physrevlett.100.027003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2007] [Indexed: 05/25/2023]
Abstract
We establish a condition for the perturbative stability of zero energy nodal points in the quasiparticle spectrum of superconductors in the presence of coexisting commensurate orders. The nodes are found to be stable if the Hamiltonian is invariant under time reversal followed by a lattice translation. The principle is demonstrated with a few examples. Some experimental implications of various types of assumed order are discussed in the context of the cuprate superconductors.
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Affiliation(s)
- E Berg
- Department of Physics, Stanford University, Stanford, California 94305-4045, USA
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Berg E, Fradkin E, Kim EA, Kivelson SA, Oganesyan V, Tranquada JM, Zhang SC. Dynamical layer decoupling in a stripe-ordered high-T(c) superconductor. Phys Rev Lett 2007; 99:127003. [PMID: 17930544 DOI: 10.1103/physrevlett.99.127003] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2007] [Indexed: 05/25/2023]
Abstract
In the stripe-ordered state of a strongly correlated two-dimensional electronic system, under a set of special circumstances, the superconducting condensate, like the magnetic order, can occur at a nonzero wave vector corresponding to a spatial period double that of the charge order. In this case, the Josephson coupling between near neighbor planes, especially in a crystal with the special structure of La(2-x)Ba(x)CuO(4), vanishes identically. We propose that this is the underlying cause of the dynamical decoupling of the layers recently observed in transport measurements at x = 1/8.
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Affiliation(s)
- E Berg
- Department of Physics, Stanford University, Stanford, California 94305-4060, USA
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Abstract
We model the Fermi surface of the cuprates by one-dimensional nested parts near (0, pi) and (pi, 0) and unnested parts near the zone diagonals. Fermions in the nested regions form 1D spin liquids and develop spectral gaps below some approximately T*, but superconducting order is prevented by 1D phase fluctuations. We show that the Josephson coupling between these order parameters locks their relative phase at pi at the crossover scale T**<T*. Below T**, the system response becomes two dimensional, and the system displays Nernst effect. The remaining total phase gets locked at Tc<T**, at which the system develops a (quasi-) long-range superconducting order.
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Affiliation(s)
- A M Tsvelik
- Department of Condensed Matter Physics and Materials Science, Brookhaven National Laboratory, Upton, New York 11973-5000, USA
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Abstract
We present studies of the electronic structure of La(2-x)BaxCuO4, a system where the superconductivity is strongly suppressed as static spin and charge orders or "stripes" develop near the doping level of x = (1/8). Using angle-resolved photoemission and scanning tunneling microscopy, we detect an energy gap at the Fermi surface with magnitude consistent with d-wave symmetry and with linear density of states, vanishing only at four nodal points, even when superconductivity disappears at x = (1/8). Thus, the nonsuperconducting, striped state at x = (1/8) is consistent with a phase-incoherent d-wave superconductor whose Cooper pairs form spin-charge-ordered structures instead of becoming superconducting.
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Affiliation(s)
- T Valla
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, NY 11973, USA.
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Abstract
The behaviour of electrons in solids is well described by Landau's Fermi-liquid theory, which predicts that although electrons in a metal interact, they can still be treated as well defined fermions, which are called 'quasiparticles'. At low temperatures, the ability of quasiparticles to transport heat is given strictly by their ability to transport charge, as described by a universal relation known as the Wiedemann-Franz law, which hitherto no material has been known to violate. High-temperature superconductors have long been thought to fall outside the realm of Fermi-liquid theory, as suggested by several anomalous properties, but this has yet to be shown conclusively. Here we report an experimental test of the Wiedemann-Franz law in the normal state of a copper-oxide superconductor, (Pr,Ce)2CuO4, which reveals that the elementary excitations that carry heat in this material are not fermions. This is compelling evidence for the breakdown of Fermi-liquid theory in high-temperature superconductors.
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Affiliation(s)
- R W Hill
- Canadian Institute for Advanced Research, Department of Physics, University of Toronto, Toronto, Ontario M5S 1A7, Canada
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