Large negative thermal Hall conductivity in cuprate Mott insulators

ORAL

Abstract

A large negative thermal Hall signal kxy has recently been observed to appear in the pseudogap phase of cuprates [1]. This signal persists to zero doping, in the antiferromagnetic Mott insulator La2CuO4. While it is clearly not due to electrons, this kxy signal could come from magnons, or phonons — or more exotic excitations. To shed light on the underlying mechanism, we measured kxy in two additional cuprate Mott insulators: Nd2CuO4 and Sr2CuO2Cl2 . We observe a large negative kxy signal in both materials. Because of the absence of spin canting in either of these materials without apical oxygens, and because of the absence of any change in kxy upon crossing different magnetic states in Nd2CuO4, we infer that magnons are not the heat carriers responsible for kxy. The similarity in the temperature dependence of kxy and kxx suggests a phonon scenario. If so, the mechanism whereby the pseudogap phase confers chirality to phonons remains to be elucidated.

[1] Grissonnanche et al., Nature 571, 376 (2019).

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Presenters

  • Marie-Eve Boulanger

    • Universite de Sherbrooke
    • University of Sherbrooke

Authors

  • Marie-Eve Boulanger

    • Universite de Sherbrooke
    • University of Sherbrooke

  • Gael Grissonnanche

    • Universite de Sherbrooke
    • University of Sherbrooke

  • Maxime Dion

    • Universite de Sherbrooke

  • Etienne Lefrancois

    • Universite de Sherbrooke

  • Ruixing Liang

    • Department of Physics & Astronomy, University of British Columbia
    • University of British Columbia
    • University of British Colombia

  • Walter N Hardy

    • Department of Physics & Astronomy, University of British Columbia
    • University of British Colombia

  • Douglas A Bonn

    • University of British Columbia
    • University of British Colombia

  • 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

  • Louis Taillefer

    • Universite de Sherbrooke
    • University of Sherbrooke