Superconductivity in Twisted Double Bilayer Graphene Stabilized by WSe<sub>2</sub>

ORAL

Abstract

Twisted double bilayer graphene (TDBG) provides a fascinating platform to study correlated electron physics, where the bandwidth and band topology can be tuned by gate voltages. Although correlated insulating states, anomalous hall effect, and signatures of non-trivial band topology have been realized, superconductivity has not, despite its appearance in other graphene-based van der Waals heterostructures. Here, we report on the observation of superconductivity in TDBG proximitized with semiconducting WSe2, based on two WSe2/TDBG samples with twist angles of 1.24 and 1.37 degrees. Superconductivity emerged in the first moiré valence band for the 1.24 degree sample, and in the conduction band for the 1.37 degree sample, both with a small critical temperature of ~100 mK. Superconductivity was confirmed by non-linear current-voltage characteristics, and suppression of critical current with perpendicular magnetic field showing phase coherent Fraunhofer-like patterns. In both cases, low-field Hall measurements reveal that superconductivity emerges from a spin-valley degenerate metal, but close to a van Hove singularity and adjacent to a region susceptible to interaction-induced spin polarization. These results highlight the correlation between a high density of states and the emergence of superconductivity in TDBG while indicating a possible role for spin fluctuations in the pairing.

*Thanks to: European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme under grant agreement No 951541; Stewart Blusson; Quantum Matter Institute; Natural Sciences and Engineering Research Council of Canada; Canada Foundation for Innovation; Canadian Institute for Advanced Research

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Presenters

  • Ruiheng Su

    • The University of British Columiba

Authors

  • Ruiheng Su

    • The University of British Columiba

  • Manabendra Kuiri

    • University of British Columbia

  • Kenji Watanabe

    • National Institute for Materials Science
    • Research Center for Functional Materials, National Institute of Materials Science
    • Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-044, Japan
    • NIMS
    • Research Center for Functional Materials, National Institute for Materials Science
    • National Institute for Materials Science, Japan
    • Research Center for Functional Materials, National Institute for Materials Science, Tsukuba, Japan
    • NIMS Japan

  • Takashi Taniguchi

    • National Institute for Materials Science
    • Kyoto Univ
    • International Center for Materials Nanoarchitectonics, National Institute of Materials Science
    • Kyoto University
    • International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-044, Japan
    • International Center for Materials Nanoarchitectonics, National Institute for Materials Science
    • National Institute for Materials Science, Japan
    • National Institute For Materials Science
    • NIMS
    • National Institute for Material Science
    • International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Japan
    • NIMS Japan

  • Joshua Folk

    • University of British Columbia
    • Physics and Astronomy, University of British Columbia