Nontrivial superconductivity signatures in topological MoTe2−xSx crystals

ORAL

Abstract

Topological Weyl semimetals (TWSs) and topological Dirac semimetals have broadened the classification of topological phases and provide new platforms for studying topological superconductivity. Here, we report a systematic study of superconductivity in sulfur-doped Td-phase MoTe2 with enhanced Tc compared with type-II TWS MoTe2. We found that Td-phase S-doped MoTe2 (MoTe2−xSx, x ∼ 0.2) is a two-band s-wave bulk superconductor (superconducting gap∼0.13 meV and 0.26 meV), where the superconducting behavior can be explained by the s+− pairing model. We also used scanning tunneling spectroscopy to detect a relatively large surface superconducting gap (∼1.7 meV), suggestive of topologically nontrivial superconductivity based on the pairing of Fermi arc surface states. Indeed, a comparison of the quasi-particle interference patterns with band-structure calculations indicates Fermi arcs in MoTe2−xSx. Our results demonstrates that the Td-phase MoTe2−xSx might be a promising topological superconductor candidate and also a unique material for studying s+− superconductivity.

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Presenters

  • Yanan Li

    Department of Physics and Materials Research Institute, Pennsylvania State University, Pennsylvania State University

Authors

  • Yanan Li

    Department of Physics and Materials Research Institute, Pennsylvania State University, Pennsylvania State University

  • Qiangqiang Gu

    Peking University, International Center for Quantum Materials, Peking University

  • Chen Chen

    Fudan University, Department of Physics, Fudan University, Physics Department, Fudan University

  • Nitin Samarth

    Department of Physics and Materials Research Institute, Pennsylvania State University, Physics, Penn State University, Physics, The Pennsylvania State University, Pennsylvania State University, Department of Physics, Pennsylvania State University, Materials Research Institute, Pennsylvania State University, Department of Physics, The Pennsylvania State University, Physics, Pennsylvania State University

  • Tong Zhang

    Fudan University, Physics Department, Fudan University

  • Ji Feng

    Peking University, International Center for Quantum Materials, Peking University

  • Jian Wang

    International Center for Quantum Materials, Peking University