Magic-angle twisted trilayer graphene: Inhomogeneous twisted superconductor showing competing magnetic order

ORAL

Abstract

Twisted graphene systems form an exciting platform for studying the effects of strong electronic correlations arising from flat bands. Members of the twisted graphene family like magic-angle twisted bilayer graphene and magic-angle twisted trilayer graphene (MATTG) exhibit superconductivity. The origin of this unconventional superconductivity largely remains elusive. In our experiments with the MATTG, we observe evidence of MATTG being an inhomogeneous superconductor due to the presence of moiré solitons and twistons; creating weak links in the superconductor which behave like a network of Josephson junctions. We gather large statistics on the switching from the superconducting to the normal state - the switching distributions. Our experiments establish the technique of switching measurements as a novel way to probe these superconductors. These distributions are studied with the variation of temperature and in-plane magnetic field providing evidence of a competing magnetic order in the ground state. Additionally, a non-linear exponent extracted from DC I-V data allows us to infer the superfluid stiffness Js in the system, providing a first experimental estimate of Js in MATTG.

*We acknowledge support from DST and DAE, India.

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Presenters

  • Ayshi Mukherjee

    • Tata Institute of Fundamental Research

Authors

  • Ayshi Mukherjee

    • Tata Institute of Fundamental Research

  • Surat Layek

    • Tata Institute of Fundamental Research

  • Heena Agarwal

    • Tata Institute of Fundamental Research
    • Tata Institute of Fundamental Research Mumbai

  • Subhajit Sinha

    • Tata Institute of Fundamental Research

  • Joydip Sarkar

    • Tata Institute of Fundamental Research, Mumbai

  • L. D. Varma Sangani

    • Tata Institute of Fundamental Research (TIFR)

  • Alisha H Marchawala

    • Tata Institute of Fundamental Research

  • 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

  • Mandar M Deshmukh

    • Tata Institute of Fundamental Research (TIFR)