Scanning tunneling microscopy of gated twisted bilayer graphene: Suppression of tunneling density of states due to electronic correlations

ORAL

Abstract

‘Magic’ angle(~1.1°) twisted bilayer graphene(TBG) is predicted to host narrow, non-dispersive electronic bands, where the kinetic energy of electrons becomes much smaller than Coulomb interactions. Recent transport measurements in this system showed insulating behavior and superconductivity around half filling of the bands, key signatures of the strongly correlated electronic systems. But the detailed electronic structure and the many-body properties of this system are still not well-understood. We used scanning tunneling microscopy and spectroscopy to measure gated TBG with angles ranging from 0.9° to 2°. When the twist angle was close to the magic angle, at certain carrier densities, we observed strong suppression of the tunneling density of states at the Fermi level associated with electron-electron interactions. Our results may deepen the understanding of strongly correlated behavior in magic angle TBG.

*This work was supported by NSF (Partly through grants DMR 1744011 and DMR 1753306). Y. C. was supported by Kwanjeong Educational Foundation.

–

Presenters

  • Youngjoon Choi

    • Department of Physics, California Institute of Technology,1200 East California Boulevard, Pasadena, California 91125, USA
    • Department of Physics, California Institute of Technology
    • Caltech

Authors

  • Youngjoon Choi

    • Department of Physics, California Institute of Technology,1200 East California Boulevard, Pasadena, California 91125, USA
    • Department of Physics, California Institute of Technology
    • Caltech

  • Jeannette Kemmer

    • Watson Laboratory of Applied Physics, California Institute of Technology, 1200 East California Boulevard, Pasadena, California 91125, USA
    • Watson Laboratory of Applied Physics, California Institute of Technology
    • Caltech

  • Harpreet Singh Arora

    • Watson Laboratory of Applied Physics, California Institute of Technology, 1200 East California Boulevard, Pasadena, California 91125, USA
    • Watson Laboratory of Applied Physics, California Institute of Technology
    • Caltech

  • Robert Polski

    • Watson Laboratory of Applied Physics, California Institute of Technology, 1200 East California Boulevard, Pasadena, California 91125, USA
    • Watson Laboratory of Applied Physics, California Institute of Technology
    • Caltech

  • Yiran Zhang

    • Department of Physics, California Institute of Technology,1200 East California Boulevard, Pasadena, California 91125, USA
    • Department of Physics, California Institute of Technology
    • Caltech

  • Hechen Ren

    • Watson Laboratory of Applied Physics, California Institute of Technology, 1200 East California Boulevard, Pasadena, California 91125, USA
    • Harvard University
    • Watson Laboratory of Applied Physics, California Institute of Technology
    • Caltech
    • Physics, California Institute of Technology

  • 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

    • National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 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
    • 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
    • NIMS
    • National Institute for Material Science
    • National Institute for Materials Science, Japan
    • National Institute for Materials Science, 1-1 Namiki, Tsukuba, Japan
    • National Institute for Materials Science , 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
    • 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

  • Stevan Nadj-Perge

    • Watson Laboratory of Applied Physics, California Institute of Technology, 1200 East California Boulevard, Pasadena, California 91125, USA
    • Watson Laboratory of Applied Physics, California Institute of Technology
    • Caltech