Studying the broken symmetry states of Bernal-stacked bilayer graphene in a magnetic field by scanning tunneling microscope

ORAL

Abstract

Bernal-stacked bilayer graphene forms eight-fold degenerate lowest Landau levels with valley, spin and orbital degree of freedoms under a magnetic field. The Landau level degeneracy can be lifted by electron-electron interactions and leads to a rich set of symmetry-breaking ground states. We use a dilution refrigerator scanning tunneling microscope (STM) to study the ground states of a back-gated bilayer graphene sample under high magnetic field. With a combination of gate-dependent spectroscopy measurement and real-space imaging of the wavefunctions, we study the symmetry-breaking ground states of the lowest Landau level at each integer fillings. Our study reveals how the electron-electron interactions and external field tune the ground state of integer quantum Hall states in bilayer graphene. This research also paves the way for studying fractional quantum Hall states in bilayer graphene with STM.

*This work is supported by grants from Moore, ONR, DOE, and ARO-MURI.

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Presenters

  • Yuwen Hu

    • Princeton University

Authors

  • Yuwen Hu

    • Princeton University

  • Yen-Chen Tsui

    • Princeton University

  • Minhao He

    • Princeton University

  • Umut Kamber

    • Princeton 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

  • Ali Yazdani

    • Princeton University