Fermi surface transformation across the pseudogap critical point in the cuprate Nd-LSCO from thermoelectric measurements

ORAL

Abstract

In cuprate superconductors, the nature of the pseudogap phase and its interplay with superconductivity are still unclear. Its onset at a doping p* is characterized by a drop in the carrier density n from n = 1+p above p* to n = p below p* [1]. In Nd0.4La1.6-xSrxCuO4 (Nd-LSCO), this shows up as a low-temperature upturn in the resistivity ρ and Hall coefficient RH at dopings below p* = 0.23 [2]. Here we present a series of thermoelectric measurements in Nd-LSCO across p*, in magnetic fields large enough to suppress superconductivity. For a heat current in the CuO2 planes, the Seebeck coefficient S shows a large increase at low temperature below p*, confirming the loss of carrier density. Application of pressure suppresses the low-T upturn in S/T, as it did the upturn in ρ and RH [3]. For a heat current perpendicular to the CuO2 planes, we find that S is isotropic for p > p*, i.e. Sc/T and Sa/T are equal (and positive) in the T=0 limit. In sharp contrast, Sc becomes negative at low temperature when p < p*, revealing a profound change in the Fermi surface topology across p*.
[1] Badoux et al., Nature 531, 210 (2016)
[2] Collignon et al., Phys. Rev. B 95, 224517 (2017)
[3] Doiron-Leyraud et al., Nature Comm. 8, 2044 (2017).

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Presenters

  • Adrien Gourgout

    • Universite de Sherbrooke
    • University of Sherbrooke

Authors

  • Adrien Gourgout

    • Universite de Sherbrooke
    • University of Sherbrooke

  • Clement Collignon

    • JEIP, College de France
    • University of Sherbrooke

  • Amirreza Ataei

    • University of Sherbrooke

  • Sven Badoux

    • Universite de Sherbrooke
    • University of Sherbrooke

  • Gael Grissonnanche

    • Universite de Sherbrooke
    • University of Sherbrooke

  • Marie-Eve Boulanger

    • Universite de Sherbrooke
    • University of Sherbrooke

  • Francis Laliberte

    • Universite de Sherbrooke
    • University of Sherbrooke

  • Jianshi Zhou

    • Geological Sciences, University of Texas at Austin
    • Department of Mechanical Engineering, The University of Texas at Austin
    • Walker Department of Mechanical Engineering, University of Texas at Austin
    • Department of Mechanical Engineering, University of Texas at Austin
    • The University of Texas at Austin
    • University of Texas at Austin
    • University of Texas
    • Materials Science and Engineering program, Department of Mechanical Engineering, University of Texas at Austin

  • Qianli Ma

    • McMaster University

  • Bruce D. Gaulin

    • Physics, McMaster University
    • McMaster Univ
    • McMaster University
    • Department of Physics & Astronomy, McMaster University

  • Nicolas Doiron-Leyraud

    • Universite de Sherbrooke
    • University of Sherbrooke

  • Louis Taillefer

    • Universite de Sherbrooke
    • University of Sherbrooke