Thermal Hall conductivity in the Kitaev spin liquid candidate α-RuCl<sub>3</sub>

ORAL

Abstract

The material α-RuCl3 has been extensively researched as a potential candidate for Kitaev quantum spin liquid, whose low-energy excitations are expected to be Majorana fermions. Note that α-RuCl3 orders antiferromagnetically at low temperature, under TN = 7 K, but an external magnetic field in the plane, greater than H∥ = 7 T, removes this order. The question is whether or not there is, over a range of fields greater than 7 T, an orderless region that harbours a liquid state of quantum spin. The recent announcement of a quantized thermal Hall conductivity κxy at H∥ > 7 T by Kasahara et al. [Kasahara et al., Nature 559, 227 (2018)] would be the first direct evidence of itinerant Majorana fermions in a quantum spin liquid state. In the study we present here, we examine the origin of κxy in α-RuCl3. The comparison between the longitudinal thermal conductivity κxx and κxy suggests that κxy is mainly dominated by phonons - questioning the possibility of a quantified κxy. In addition, depending on H∥, we do not see an intermediate region between the antiferromagnetic state under 7 T and the state of polarized spins at strong magnetic field, thus leaving little room for a quantum spin liquid state.

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Presenters

  • Etienne Lefrancois

    • Universite de Sherbrooke (Canada)
    • Universite de Sherbrooke

Authors

  • Etienne Lefrancois

    • Universite de Sherbrooke (Canada)
    • Universite de Sherbrooke

  • Gael Grissonnanche

    • Institut Quantique, Département de physique & RQMP, Université de Sherbrooke
    • Universite de Sherbrooke (Canada)
    • Universite de Sherbrooke
    • Cornell University

  • Adrien Gourgout

    • Institut Quantique, Département de physique & RQMP, Université de Sherbrooke
    • Universite de Sherbrooke (Canada)
    • Universite de Sherbrooke

  • Paula J Kelley

    • Materials Science and Technology Division, Oak Ridge National Laboratory

  • Jiaqiang Yan

    • Materials Science and Technology Division, Oak Ridge National Lab
    • Oak Ridge National Laboratory
    • University of Tennessee
    • Oak Ridge National Lab
    • Materials Science and Technology Division, Oak Ridge National Laboratory
    • Materials Science and Technology, Oak Ridge National Laboratory
    • Oak Ridge National Laboratory, Materials Science and Technology Division

  • Christian Balz

    • Neutron Scattering Division, Oak Ridge National Laboratory

  • David George Mandrus

    • Materials Science and Technology Division, Oak Ridge National Labratory
    • Materials Science and Engineering, University of Tennessee
    • Department of Materials Science and Engineering, University of Tennessee
    • University of Tennessee
    • Department of Materials Science and Engineering, University of Tennessee Knoxville
    • Department of Materials Science & Engineering, University of Tennessee, Knoxville, Tennessee 37996, USA
    • Oakridge National Laboratory
    • Materials Science and Engineering, University of Tennessee, Knoxville
    • Oak Ridge National Laboratory
    • University of Tennessee - Knoxville
    • Materials Science and Technology Division, Oak Ridge National Laboratory
    • Department of Physics, University of Tennessee Knoxville
    • Materials Science and Technology, Oak Ridge National Laboratory
    • Oak Ridge National Laboratory, Materials Science and Technology Division
    • Department of Materials Science, The University of Tennessee
    • University of Tennessee, Knoxville

  • Stephen E Nagler

    • Oak Ridge National Lab
    • Oak Ridge National Laboratory
    • Oakridge National Laboratory
    • Neutron Scattering Division, Oak Ridge National Laboratory

  • Nicolas Doiron-Leyraud

    • Universite de Sherbrooke (Canada)
    • Universite de Sherbrooke

  • Louis Taillefer

    • Institut Quantique, Département de physique & RQMP, Université de Sherbrooke
    • Universite de Sherbrooke (Canada)
    • Universite de Sherbrooke
    • Université de Sherbrooke