Tunable Excitons in Rhombohedral Trilayer Graphene

ORAL

Abstract

Rhombohedral stacked multilayer graphene is a unique material where the bandgap can be continuously tuned by an out-of-plane electric field. It hosts excitons with unconventional optical selection rule and provides a novel platform to study exciton physics in the context of valley pseudospin and band topology. We observed tunable exciton states in rhombohedral trilayer graphene via a photocurrent spectroscopy technique. Unlike in AB-stacked bilayer graphene, the optical spectrum of rhombohedral trilayer graphene is dominated by exciton p and d states, while the s exciton state becomes completely dark. This observation is a direct consequence of the pseudospin texture near the band extrema. I will also discuss the moire effects on the exciton physics in a trilayer graphene/hBN superlattice.

*CIQM, NSF DMR-2225925

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Publication: non

Presenters

  • Zhengguang Lu

    • Massachusetts Institute of Technology MIT

Authors

  • Zhengguang Lu

    • Massachusetts Institute of Technology MIT

  • Xiaowei Zhang

    • University of Washington

  • Tianyi Han

    • Massachusetts Institute of Technology MIT

  • Tonghang Han

    • Massachusetts Institute of Technology MIT

  • Dasol Kim

    • Massachusetts Institute of Technology
    • Massachusetts Institute of Technology MIT

  • 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

  • Ting Cao

    • University of Washington
    • Department of Materials Science & Engineering, University of Washington

  • Long Ju

    • Massachusetts Institute of Technology MIT