Tuning Superconductivity in Spin-Orbit Bernal Bilayer Graphene by Interfacial Twisting

ORAL

Abstract

Bernal bilayer graphene (BLG) coupled to tungsten diselenide (WSe2) features an extraordinary order-of-magnitude enhancement in superconducting Tc and establishes an ultra-clean platform for exploring various correlated ground states. Here, we show that by controlling the interfacial twist angle between BLG and WSe2, the proximitized spin-orbit coupling (SOC) as well as overall BLG phase diagram can be tuned. We map out the superconducting regions and find that superconductivity exhibits a higher Tc and onsets at higher displacement fields when Ising SOC is increased. Moreover, we discover multiple superconducting regions emerging from various broken-symmetry parent phases. By carefully mapping quantum oscillations, we further establish the dependence of nematic broken flavor symmetry on doping and the Ising strength. Our results pave the way for a detailed understanding of unconventional pairing in graphene superconductors.

*This work has been primarily supported by NSF-CAREER award (no. DMR-1753306), and the Office of Naval Research (grant no. N142112635). Nanofabrication efforts have been in part supported by the Department of Energy DOE-QIS program (DE-SC0019166). We also also acknowledge the support of the Institute for Quantum Information and Matter, an NSF Physics Frontiers Center with support of the Gordon and Betty Moore Foundation through grant no. GBMF1250.

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Presenters

  • Yiran Zhang

    • California Institute of Technology

Authors

  • Yiran Zhang

    • California Institute of Technology

  • Gal Shavit

    • California Institute of Technology

  • Etienne Lantagne-Hurtubise

    • Caltech

  • Alex Thomson

    • University of California, Davis
    • Caltech

  • Cyprian K Lewandowski

    • Florida State University

  • Kenji Watanabe

    • National Institute for Materials Science
    • NIMS
    • Research Center for Electronic and Optical Materials, National Institute for Materials Science
    • Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
    • National Institute for Material Science

  • Takashi Taniguchi

    • Kyoto Univ
    • National Institute for Materials Science
    • Research Center for Materials Nanoarchitectonics
    • Research Center for Materials Nanoarchitectonics, National Institute for Materials Science
    • National Institute for Materials Sciences
    • NIMS
    • International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
    • National Institute for Material Science
    • International Center for Materials Nanoarchitectonics, NIMS, Japan
    • International Center for Materials Nanoarchitectonics, Tsukuba
    • National Institue for Materials Science
    • Kyoto University
    • National Institute of Materials Science
    • International Center for Materials Nanoarchitectonics and National Institute for Materials Science

  • Jason F Alicea

    • Caltech

  • Felix von Oppen

    • Berlin

  • Yuval Oreg

    • Weizmann Institute of Science

  • Stevan Nadj-Perge

    • Caltech