Heat transport by delocalized spin excitations in SmB$_6$

ORAL

Abstract

Measurements of thermal conductivity at low temperatures may offer insights into the low-energy landscape of excitations in the bulk of a material. Here we report thermal transport data in the canonical Kondo insulator, SmB$_6$. In zero magnetic field, we find that the heat transport below T=1 K can be entirely accounted for by phonons, consistent with an insulating state with no long-range magnetic order. With the application of a magnetic field however, new heat carriers are introduced which are neither electrons nor phonons. We discuss these results within the framework of delocalized spin excitations, supporting a gapping of the charge, but not the spin degrees of freedom in the bulk of SmB$_6$.

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Authors

  • Michael Sutherland

    • Cavendish Laboratory, Cambridge University, UK

  • Will Toews

    • Department of Physics and Astronomy, University of Waterloo, Canada

  • Xiaoye Chen

    • Cavendish Laboratory, Cambridge University, UK

  • M. Ciomaga Hatnean

    • Department of Physics, University of Warwick, UK

  • G Balakrishnan

    • Department of Physics, University of Warwick, UK

  • Y.T. Hsu

    • Cavendish Laboratory, Cambridge University, UK

  • Suchitra Sebastian

    • Cavendish Laboratory, Cambridge University, UK

  • Rob Hill

    • Department of Physics and Astronomy, University of Waterloo, Canada