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Superconductivity in metallic twisted bilayer graphene stabilized by WSe2

Author

Listed:
  • Harpreet Singh Arora

    (California Institute of Technology
    California Institute of Technology)

  • Robert Polski

    (California Institute of Technology
    California Institute of Technology)

  • Yiran Zhang

    (California Institute of Technology
    California Institute of Technology
    California Institute of Technology)

  • Alex Thomson

    (California Institute of Technology
    California Institute of Technology
    California Institute of Technology)

  • Youngjoon Choi

    (California Institute of Technology
    California Institute of Technology
    California Institute of Technology)

  • Hyunjin Kim

    (California Institute of Technology
    California Institute of Technology
    California Institute of Technology)

  • Zhong Lin

    (University of Washington)

  • Ilham Zaky Wilson

    (University of Washington)

  • Xiaodong Xu

    (University of Washington
    University of Washington)

  • Jiun-Haw Chu

    (University of Washington)

  • Kenji Watanabe

    (National Institute for Materials Science)

  • Takashi Taniguchi

    (National Institute for Materials Science)

  • Jason Alicea

    (California Institute of Technology
    California Institute of Technology
    California Institute of Technology)

  • Stevan Nadj-Perge

    (California Institute of Technology
    California Institute of Technology)

Abstract

Magic-angle twisted bilayer graphene (TBG), with rotational misalignment close to 1.1 degrees, features isolated flat electronic bands that host a rich phase diagram of correlated insulating, superconducting, ferromagnetic and topological phases1–6. Correlated insulators and superconductivity have been previously observed only for angles within 0.1 degree of the magic angle and occur in adjacent or overlapping electron-density ranges; nevertheless, the origins of these states and the relation between them remain unclear, owing to their sensitivity to microscopic details. Beyond twist angle and strain, the dependence of the TBG phase diagram on the alignment4,6 and thickness of the insulating hexagonal boron nitride (hBN)7,8 used to encapsulate the graphene sheets indicates the importance of the microscopic dielectric environment. Here we show that adding an insulating tungsten diselenide (WSe2) monolayer between the hBN and the TBG stabilizes superconductivity at twist angles much smaller than the magic angle. For the smallest twist angle of 0.79 degrees, superconductivity is still observed despite the TBG exhibiting metallic behaviour across the whole range of electron densities. Finite-magnetic-field measurements further reveal weak antilocalization signatures as well as breaking of fourfold spin–valley symmetry, consistent with spin–orbit coupling induced in the TBG via its proximity to WSe2. Our results constrain theoretical explanations for the emergence of superconductivity in TBG and open up avenues towards engineering quantum phases in moiré systems.

Suggested Citation

  • Harpreet Singh Arora & Robert Polski & Yiran Zhang & Alex Thomson & Youngjoon Choi & Hyunjin Kim & Zhong Lin & Ilham Zaky Wilson & Xiaodong Xu & Jiun-Haw Chu & Kenji Watanabe & Takashi Taniguchi & Jas, 2020. "Superconductivity in metallic twisted bilayer graphene stabilized by WSe2," Nature, Nature, vol. 583(7816), pages 379-384, July.
  • Handle: RePEc:nat:nature:v:583:y:2020:i:7816:d:10.1038_s41586-020-2473-8
    DOI: 10.1038/s41586-020-2473-8
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    Citations

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    Cited by:

    1. Qing Rao & Wun-Hao Kang & Hongxia Xue & Ziqing Ye & Xuemeng Feng & Kenji Watanabe & Takashi Taniguchi & Ning Wang & Ming-Hao Liu & Dong-Keun Ki, 2023. "Ballistic transport spectroscopy of spin-orbit-coupled bands in monolayer graphene on WSe2," Nature Communications, Nature, vol. 14(1), pages 1-10, December.
    2. Saisab Bhowmik & Bhaskar Ghawri & Youngju Park & Dongkyu Lee & Suvronil Datta & Radhika Soni & K. Watanabe & T. Taniguchi & Arindam Ghosh & Jeil Jung & U. Chandni, 2023. "Spin-orbit coupling-enhanced valley ordering of malleable bands in twisted bilayer graphene on WSe2," Nature Communications, Nature, vol. 14(1), pages 1-8, December.
    3. Søren Ulstrup & Yann in ’t Veld & Jill A. Miwa & Alfred J. H. Jones & Kathleen M. McCreary & Jeremy T. Robinson & Berend T. Jonker & Simranjeet Singh & Roland J. Koch & Eli Rotenberg & Aaron Bostwick , 2024. "Observation of interlayer plasmon polaron in graphene/WS2 heterostructures," Nature Communications, Nature, vol. 15(1), pages 1-9, December.
    4. Jiachen Yu & Benjamin A. Foutty & Yves H. Kwan & Mark E. Barber & Kenji Watanabe & Takashi Taniguchi & Zhi-Xun Shen & Siddharth A. Parameswaran & Benjamin E. Feldman, 2023. "Spin skyrmion gaps as signatures of strong-coupling insulators in magic-angle twisted bilayer graphene," Nature Communications, Nature, vol. 14(1), pages 1-7, December.
    5. Martin Claassen & Lede Xian & Dante M. Kennes & Angel Rubio, 2022. "Ultra-strong spin–orbit coupling and topological moiré engineering in twisted ZrS2 bilayers," Nature Communications, Nature, vol. 13(1), pages 1-8, December.
    6. Shubhayu Chatterjee & Taige Wang & Erez Berg & Michael P. Zaletel, 2022. "Inter-valley coherent order and isospin fluctuation mediated superconductivity in rhombohedral trilayer graphene," Nature Communications, Nature, vol. 13(1), pages 1-10, December.

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