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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