Signatures of the topological s+- superconducting order parameter in the type-II Weyl semimetal Td-MoTe2

ORAL

Abstract

In its orthorhombic Td polymorph, MoTe2 is a type-II Weyl semimetal, where the Weyl fermions emerge at the boundary between electron and hole pockets. Non-saturating magnetoresistance (MR) and superconductivity were also observed in Td-MoTe2. Understanding the superconductivity in Td-MoTe2, which was proposed to be topologically non-trivial, is of eminent interest. I will report high-pressure muon spin rotation experiments probing the temperature-dependent magnetic penetration depth in Td-MoTe2 [1].
A substantial increase of the superfluid density and a linear scaling with the superconducting critical temperature Tc is observed under pressure. Moreover, the superconducting order parameter in Td-MoTe2 is determined to have 2-gap s-wave symmetry. We also exclude time reversal symmetry breaking in the superconducting state with zero-field μSR experiments. Considering the strong suppression of Tc in MoTe2 by disorder, we suggest that topologically nontrivial s+- state is more likely to be realized in MoTe2 than the topologically trivial s++ state.

[1] Z. Guguchia et. al., Nature Communications 8, 1082 (2017).

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Presenters

  • Zurab Guguchia

    Columbia Univ, Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, Department of Physics, Columbia university

Authors

  • Zurab Guguchia

    Columbia Univ, Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, Department of Physics, Columbia university

  • Fabian von Rohr

    Department of Chemistry, Princeton University

  • Zurab Shermadini

    Paul Scherrer Institute, Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute

  • Alex Taekyung Lee

    Department of Applied Physics and Applied Mathematics, Columbia university

  • Soham Banerjee

    Applied Physics , University of Columbia, Columbia Univ, Brookhaven Natl Lab, Department of Applied Physics and Applied Mathematics, Columbia university

  • Andrew Wieteska

    Physics, Columbia Univ, Department of Physics, Columbia university

  • Chris Marianetti

    Columbia University, Physics, Columbia Univ, Department of Applied Physics and Applied Mathematics, Columbia university, Columbia Univ, Columbia

  • Benjamin Frandsen

    Materials Sciences Division, Lawrence Berkeley National Laboratory, Physics, University of California, Berkeley, Univ of California - Berkeley, Department of Physics, University of California, Berkeley

  • Hubertus Luetkens

    Paul Scherrer Institute, Paul Sherrer Institut, Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute

  • Zizhou Gong

    Department of Physics, Columbia university

  • Sky Cheung

    Department of Physics, Columbia university

  • Chris Baines

    Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute

  • Alexander Shengelaya

    Tbislisi State University, Department of Physics, Tbilisi State University

  • Grigol Taniashvili

    Department of Physics, Tbilisi State University

  • Abhay Pasupathy

    Columbia University, Columbia Univ, Physics, Columbia Univ, Department of Physics, Columbia university

  • Elvezio Morenzoni

    Paul Scherrer Institute, Paul Sherrer Institut, Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute

  • Simon Billinge

    Applied Physics , University of Columbia, Department of Applied Physics and Applied Mathematics, Columbia university

  • Alex Amato

    Paul Scherrer Institute, Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute

  • Robert Cava

    Department of Chemistry, Princeton University, Princeton, Princeton University, Chemistry, Princeton Univ, Princeton Univ

  • Rustem Khasanov

    Paul Scherrer Institute, Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, Laboratory for Muon-Spin Spectroscopy, Paul Scherrer Institute

  • Yasutomo Uemura

    Columbia Univ, Department of Physics, Columbia University, Columbia University, Department of Physics, Columbia university