Emerging Interlayer Coherence in Twist-Controlled Graphene Double Layers

ORAL

Abstract

In closely spaced double layer systems in the quantum Hall regime, enhanced interlayer interactions can lead to interlayer exciton condensates when each layer is at half-integer filling of the lowest Landau level. We study interlayer tunneling in double layers of graphene separated by a thin hBN tunnel barrier, where accurate rotational alignment of the graphene monolayers leads to energy and momentum conserving resonant tunneling. At half-integer layer fillings of the lowest orbital Landau level, we observe Josephson-like zero-bias tunneling conductance peaks that are insensitive to variations of layer filling factors. The zero-bias tunneling conductance peaks have a significantly narrower linewidth compared to 2D-2D tunneling resonances observed at zero magnetic field when the energy bands of the two layers are aligned, indicating that electrons occupy an interlayer coherent superposition of states in both layers. Additionally, the tunneling spectrum provides insight into the types of paired states. Our results establish twist control as key to probing interlayer exciton condensates through tunneling anomalies in double layers of two-dimensional materials.

*This work was supported by the National Science Foundation Grants No. EECS-2122476 and No. DMR- 1720595, and by the Army Research Office under Grants No. W911NF-17-1-0312 and No. W911NF-22-1-0160.

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Presenters

  • Kenneth A Lin

    • University of Texas at Austin

Authors

  • Kenneth A Lin

    • University of Texas at Austin

  • Nitin Prasad

    • Department of Chemistry and Biochemistry, University of Maryland, College Park

  • G W Burg

    • University of Texas at Austin

  • Bo Zou

    • University of Texas at Austin
    • the University of Texas at Austin

  • Keiji Ueno

    • Department of Chemistry, Graduate School of Science and Engineering, Saitama University

  • 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

  • Allan H MacDonald

    • University of Texas at Austin

  • Emanuel Tutuc

    • University of Texas at Austin