Unexpected two-fold symmetric superconductivity in few-layer NbSe2

ORAL

Abstract

Transition metal dichalcogenides (TMDs) have attracted significant interest due to properties such as layer-dependent inversion symmetry, valley-contrasted Berry curvatures, and strong spin-orbit coupling (SOC). Few-layer niobium diselenide (NbSe2) exhibits Ising SOC, which helps stabilize the superconducting state and could lead to exotic properties such as topological superconductivity. Here, we report transport measurements of few-layer NbSe2 under in-plane external magnetic fields. In contrast to the three-fold symmetry of the lattice, we observe the magnetoresistance, critical field, and differential conductance measurements all exhibit a two-fold oscillation confined to the superconducting phase. We attribute the behavior to the mixing between two closely competing pairing instabilities. Our results demonstrate the unconventional character of the pairing interaction in a few-layer TMD, opening a new avenue to search for exotic superconductivity in this family of 2D materials.

arXiv:2004.02999

*NSF DMR-1420013, iSuperseed; NNCI ECCS-1542202, Minnesota Nano Center; NSF DMR-1644779 and State of Florida, NHMFL; ONR N00014-18-1-2368; NSF DMR-1807810; Swiss National Science Foundation; David and Lucille Packard Fellowship

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Presenters

  • Brett Heischmidt

    • University of Minnesota

Authors

  • Alex Hamill

    • University of Minnesota

  • Brett Heischmidt

    • University of Minnesota

  • Egon Sohn

    • Cornell University

  • Daniel Shaffer

    • Emory University
    • University of Minnesota

  • Kan-Ting Tsai

    • University of Minnesota

  • Xi Zhang

    • University of Minnesota

  • Xiaoxiang Xi

    • Nanjing University

  • Alexey Suslov

    • National High Magnetic Field Laboratory

  • Helmuth Berger

    • Laboratory of Physics of Complex Matter, École polytechnique fédérale de Lausanne
    • EPFL
    • Ecole Polytechnique Fédérale de Lausanne

  • Laszlo Forro

    • EPFL
    • Ecole Polytechnique Fédérale de Lausanne

  • Fiona Burnell

    • Department of Physics, University of Minnesota Twin Cities
    • University of Minnesota

  • Jie Shan

    • Cornell University

  • Kin Fai Mak

    • Cornell University

  • Rafael Fernandes

    • University of Minnesota
    • School of Physics and Astronomy, University of Minnesota
    • Physics, University of Minnesota
    • School of Physics and Astronomy, University of Minnesota, Minneapolis, 55455 MN
    • School of Physics and Astronomy, University of Minnesota, Minneapolis

  • Ke Wang

    • University of Minnesota

  • Vlad Pribiag

    • University of Minnesota