Dynamic band structure in twisted bilayer graphene near the magic angle

ORAL

Abstract

A twist between the orientations of superposed 2D crystal structures leads to a moiré superstructure which can significantly alter their electronic properties. In the case of superposed graphene layers with small twist angle, the energy band flattens resulting in a slow-down of the charge carriers until, at certain “magic angles”, they come to a complete halt. In this regime, electron-electron interactions become strong leading to the emergence of new correlated phases and topologically protected ballistic channels. Using STM on gated twisted bilayer graphene samples, we study the band structure and the emergence of correlated states as a function of doping and twist-angle near the first magic angle. Far from the magic angle, we observe two van hove singularity (VHS) peaks whose separation allows us to extract the interlayer coupling. Contrary to expectation we find that the interlayer hopping is a function of the twist angle and doping. Upon approaching the magic angle the VHS merge into a single flat band which straddles the charge neutrality point. We observe a dynamic reconstruction of the band structure with gap-like features at certain fillings and a corresponding unique spatial reconstruction of the electronic wave-function.

*DOE-FG02-99ER45742, NSF DMR 1708158

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Presenters

  • Jinhai Mao

    • Department of Physics and Astronomy, Rutgers University, 136 Frelinghuysen Road, Piscataway, NJ 08855 USA

Authors

  • Jinhai Mao

    • Department of Physics and Astronomy, Rutgers University, 136 Frelinghuysen Road, Piscataway, NJ 08855 USA

  • Yuhang Jiang

    • Department of Physics and Astronomy, Rutgers University, 136 Frelinghuysen Road, Piscataway, NJ 08855 USA

  • Xinyuan Lai

    • Department of Physics and Astronomy, Rutgers University, 136 Frelinghuysen Road, Piscataway, NJ 08855 USA

  • Kenji Watanabe

    • National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305 0044, Japan
    • Advanced Materials Laboratory, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
    • National Institute for Materials Science
    • Advanced Materials Laboratory, National Institute for Materials Science, , 1-1 Namiki, Tsukuba 305-0044, Japan
    • National Institute for Material Science, 1-1 Namiki, Tsukuba 305-0044
    • National Institute of Materials Science
    • NIMS, Japan
    • Advanced Materials Laboratory, NIMS
    • National Institute for Materials Science, Tsukuba, Japan
    • National Institute for Materials Science, Japan
    • Advanced Materials Laboratory, National Institute for Materials Science
    • National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
    • National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0044, Japan
    • National Institute for Materials Science (NIMS)
    • NIMS Tsukuba
    • National Institute for Materials Science (Japan)
    • NIMS
    • National Institute for Material Science
    • National Institute for Materials Science, 1-1 Namiki, Tsukuba, Japan
    • National Institute for Materials Science , Japan
    • National Institute for Materials Science, Namiki 1-1, Tsukuba, Ibaraki 305-0044, Japan.
    • Advanced Materials Laboratory, National Institute for Materials Science, Japan
    • Advanced Materials Laboratory, National Institute for Materials Science, Tsukuba, Ibaraki 305-0044, Japan
    • National Institute for Materials Science, Tsukuba, Ibaraki 305- 0044, Japan
    • National Institute for Material Science - Japan
    • National Institute for Materials Science, Namiki Tsukuba Ibaraki, Japan
    • National Institute of Material Science
    • Advanced Material Lab, NIMS
    • Advanced Materials Laboratory, National Institute for Materials Science, Tsukuba, Japan
    • Advanced Materials Laboratory, National Institute for Materials Science, Tsukuba, Ibaraki, Japan
    • National Institute for Materials Science, Tsukuba
    • 1-1 Namiki, Tsukuba, National Institute for Materials Science
    • NIMS/Tsukuba
    • National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044 Japan
    • National Institute for Materials Science, Namiki, 305-0044, Japan
    • National Institute for Material Science, Japan
    • Advanced Materials Laboratory, NIMS, Japan
    • Columbia University
    • Advanced Materials Labaratory, National Institute for Materials Science
    • National Institute of Material Science, 1-1 Namiki, Tsukuba, Ibaraki 205-0044, Japan
    • National Institute of Materials Science, Japan

  • Takashi Taniguchi

    • Advanced Materials Laboratory, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
    • National Institute for Materials Science, Japan
    • National Institute for Materials Science (Japan)
    • National Institute for Materials Science
    • NIMS
    • Kyoto University
    • National Institute for Materials Science, Namiki 1-1, Tsukuba, Ibaraki 305-0044, Japan.
    • National Institute of Materials Science

  • Eva Y. Andrei

    • Department of Physics and Astronomy, Rutgers University, 136 Frelinghuysen Road, Piscataway, NJ 08855 USA