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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