A Tunable Monolithic Superconducting Quantum Interference Device in Twisted Bilayer Graphene

ORAL

Abstract

We present a Superconducting Quantum Interference Device (SQUID) in Magic-Angle Twisted Bilayer Graphene (MATBG) [1], building on previous single-junction realizations [2, 3]. The superconducting phase difference is controlled through the magnetic field. We observe magneto-oscillations of the critical current, demonstrating long-range coherence agreeing with an effective charge of 2e for the superconducting charge carriers. We tune to both asymmetric and symmetric SQUID configurations by electrostatically controlling the critical currents through the junctions. With this tunability, we study the inductances in the device, finding values above 100nH. Furthermore, we directly observe the current-phase relation of one of the Josephson junctions of the device.

[1] Cao, Y. et al. Unconventional superconductivity in magic-angle graphene superlattices. Nature 556, 43–50 (2018)

[2] de Vries, F.K. et al. Gate-defined Josephson junctions in magic-angle twisted bilayer graphene. Nat. Nanotechnol. 16, 760–763 (2021)

[3] Rodan-Legrain, et al. Highly tunable junctions and non-local Josephson effect in magic-angle graphene tunnelling devices. Nat. Nanotechnol. 16, 769–775 (2021)

[4] Portolés, E. et al. A Tunable Monolithic SQUID in Twisted Bilayer Graphene. arXiv:2201.13276 (2022)

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Publication: Portolés, E. et al. A Tunable Monolithic SQUID in Twisted Bilayer Graphene. arXiv:2201.13276 (2022)

Presenters

  • Elías Portolés

    • ETH Zurich

Authors

  • Elías Portolés

    • ETH Zurich

  • Shuichi Iwakiri

    • ETH Zurich

  • Giulia Zheng

    • ETH Zurich

  • Peter Rickhaus

    • Qnami

  • 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

  • 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

  • Thomas Ihn

    • ETH Zurich

  • Klaus Ensslin

    • ETH Zurich

  • Folkert K de Vries

    • ETH Zurich