High-resolution Landau level spectroscopy of magic-angle twisted bilayer graphene

ORAL

Abstract

Spectroscopy with scanning tunneling microscopy (STM) in a high magnetic field can be used to probe the quantization of the density of states into Landau levels (LL), which provides important information on electronic properties such as the relevance of broken symmetries and the presence or absence of Dirac cones. We apply this technique to study gated magic-angle twisted bilayer graphene (MATBG) devices, for which recent magnetotransport studies have reported transitions in the LL fan diagrams as a function of the filling of electrons in MATBG’s flat bands [1-3]. These reported changes correlate with the appearance of various correlated insulating, magnetic, and superconducting phases. Our STM measurements are carried out in a dilution-fridge system allowing us to resolve the energy of the LL with high resolution and to probe MATBG devices as a function of filling of its flat band. We will describe these measurements, their connection to the magnetotransport studies, and their interpretations in terms of microscopic properties of MATBG as a function of electron density.

[1] Y. Cao et al. Nature 556, 43 (2018)
[2] M. Yankowitz et al. Science 363, 1059 (2019)
[3] X. Lu et al. arXiv:1903.06513

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Presenters

  • Dillon Wong

    Joseph Henry Laboratories & Department of Physics, Princeton University

Authors

  • Dillon Wong

    Joseph Henry Laboratories & Department of Physics, Princeton University

  • Kevin Nuckolls

    Joseph Henry Laboratories & Department of Physics, Princeton University

  • Myungchul Oh

    Joseph Henry Laboratories & Department of Physics, Princeton University

  • Biao Lian

    Princeton Center for Theoretical Science, Princeton University, Princeton University, Physics, Princeton University

  • Kenji Watanabe

    National Institute for Materials Science, Japan, National Institute for Material Science, National Institute for Materials Science, National Institute for Materials Science, Tsukuba, Research Center for Functional Materials, NIMS, nims, Advanced Materials Laboratory, National Institute for Materials Science, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan, NIMS, National Institute for Material Science - Japan, NIMS Tsukuba, National Institute for Materials Science, Namiki 1-1, Ibaraki 305-0044, Japan., National Institute for Materials Science (NIMS), National Institute for Materials Science,Tsukuba, Ibaraki 305-0047, Japan, Advanced Materials Laboratory, NIMS, Japan, National Institute for Materials Science,1-1 Namiki, Tsukuba, 305-0044, Japan, National Institute of Materials Science, National Institute for Materials Science, University of Tsukuba, National Institute for Materials Science, Tsukuba, Japan, National Institute for Material Science, Japan, National Institue for Material Science, Tsukuba, Advanced Materials Laboratory, NIMS, Advanced Materials Laboratory, National Institute for Materials Science, Tsukuba 305-0044, Japan, Advanced Matrials Lab, NIMS, National Institute for Material Science, Tsukuba, Japan, National institute for materials science, NIMS-Tsukuba, NIMS, Japan, National Institute for Materials Science, Namiki Tsukuba Ibaraki, Japan, NIRM, Advanced Materials Laboratory, National Institute for Materials Science, Tsukuba, Japan, NIMS Japan, National Institute for Materials Science, Tsukuba, Ibaraki 305-0044, Japan, Research Center for Functional Materials, National Institute for Materials Science, Tsukuba, Ibaraki, Japan, Advanced Materials Laboratory, National Institute of Materials Science, Advanced Materials Laboratory, National Institute for Materials Science 1-1 Namiki, Tsukuba, 305-0044, Japan, National Institute of Material Science, 1-1 Namiki, Tsukuba 305-0044, Japan, National Institute for Material Science (Japan), Physics, NIMS, National Institute of Materials Science, Japan, National Institute of Materials Science (NIMS), National Institute of Materials Science, Tsukuba, Ibaraki 305-0044, Japan, NIMS - Tsukuba

  • Takashi Taniguchi

    National Institute for Materials Science, Japan, National Institute for Material Science, National Institute for Materials Science, National Institute for Materials Science, Tsukuba, Research Center for Functional Materials, NIMS, nims, Advanced Materials Laboratory, National Institute for Materials Science, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan, NIMS, National Institute for Material Science - Japan, NIMS Tsukuba, National Institute for Materials Science, Namiki 1-1, Ibaraki 305-0044, Japan., National Institute for Materials Science (NIMS), National Institute for Materials Science,Tsukuba, Ibaraki 305-0047, Japan, Advanced Materials Laboratory, NIMS, Japan, National Institute for Materials Science,1-1 Namiki, Tsukuba, 305-0044, Japan, National Institute of Materials Science, National Institute for Materials Science, University of Tsukuba, National Institute for Materials Science, Tsukuba, Japan, National Institue for Material Science, Tsukuba, Advanced Materials Laboratory, NIMS, Advanced Materials Laboratory, National Institute for Materials Science, Tsukuba 305-0044, Japan, Advanced Matrials Lab, NIMS, National Institute for Material Science, Tsukuba, Japan, National institute for materials science, NIMS-Tsukuba, NIMS, Japan, National Institute for Materials Science, Namiki Tsukuba Ibaraki, Japan, Advanced Materials Laboratory, National Institute for Materials Science, Tsukuba, Japan, NIMS Japan, National Institute for Materials Science, Tsukuba, Ibaraki 305-0044, Japan, Research Center for Functional Materials, National Institute for Materials Science, Tsukuba, Ibaraki, Japan, Advanced Materials Laboratory, National Institute of Materials Science, Advanced Materials Laboratory, National Institute for Materials Science 1-1 Namiki, Tsukuba, 305-0044, Japan, National Institute of Material Science, 1-1 Namiki, Tsukuba 305-0044, Japan, National Institute for Material Science (Japan), Physics, NIMS, National Institute of Materials Science, Japan, National Institute of Materials Science, Tsukuba, Ibaraki 305-0044, Japan, NIMS - Tsukuba

  • Andrei Bernevig

    Physics, Princeton University, Princeton Center for Theoretical Science, Princeton University, Princeton University, Department of Physics, Princeton university, Physics department, Princeton University

  • Ali Yazdani

    Princeton University, Joseph Henry Laboratories & Department of Physics, Princeton University, Princeton Univ, Department of Physics, Princeton University