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Imaging Commensurate Minimally Twisted Bilayer Graphene Aligned to Hexagonal Boron Nitride

ORAL

Abstract

Aligning magic-angle twisted bilayer graphene (TBG) with a hexagonal boron nitride (hBN)

substrate reveals the hidden non-trivial topology of the flat band through the appearance of a

quantum anomalous Hall effect (QAHE) in transport measurements. 1 The commensuration of the

two sets of Moiré patterns (graphene-graphene and graphene-hBN) is expected to occur, due to

the 1.8% difference in the lattice constants of graphene and hBN, only at a TBG twist angle of .

Surprisingly, by using low temperature scanning tunneling microscopy (STM) and spectroscopy

(STS), we find a locally stable commensurate double Moiré pattern for , suggesting strong

lattice relaxation effects that favor the alignment of the two Moiré patterns even for twist angles

that differ substantially from estimates based on rigid lattice calculations. We observe large

domains (200x200nm) of perfectly aligned double Moiré patterns separated by domain walls

where the built-up strain is released. Furthermore, STS reveals gaps at fractional fillings of the

flat band that increase in the presence of a magnetic field indicating that alignment with hBN

reveals an intrinsic non-trivial band topology even for twist angles far from the magic angle.

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Publication: Serlin, M. et al. Intrinsic quantized anomalous Hall effect in a moiré heterostructure. Science<br>367, 900, doi:10.1126/science.aay5533 (2020).

Presenters

  • Xinyuan Lai

    Rutgers University, Department of Physics and Astronomy,136 Frelinghuysen Rd, Piscataway, 08854, New Jersey, USA

Authors

  • Xinyuan Lai

    Rutgers University, Department of Physics and Astronomy,136 Frelinghuysen Rd, Piscataway, 08854, New Jersey, USA

  • Kenji Watanabe

    National Institute for Materials Science, Tsukuba, Japan, National Institute for Materials Science, NIMS, Research Center for Functional Materials, National Institute for Materials Science, Tsukuba, Ibaraki 305-0044, Japan, Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan., Research Center for Functional Materials, National Institute for Materials Science, Advanced, Materials Laboratory, NIMS, 3 National Institute for Materials Science, Tsukuba, Japan, National Institute for Materials Science; 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan, National Institute of Materials Science, Tsukuba, Japan, National Institute of Materials Science, 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, Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan, Research Center for Functional Materials, Research Center for Functional Materials, National Institute for Materials Science, Tsukuba, Japan, Research Center for Functional Materials, National Institute for Materials Science, Japan, Research Center for Functional Materials, National Institute for Materials Science, 1-1Namiki, Tsukuba 305-0044, Japan, National Institute for Material Science, Japan, National Institute for Material Science, National Institute of Material Sciences, Japan, NIMS, Tsukuba, 2National Institute for Materials Science, Namiki 1-1, Ibaraki 305-0044, Japan., National Institute of Materials Science, Tsukuba, Ibaraki 305-0044, Japan, National Institute for Materials Science Japan, NIMS, Japan, nims, National Institute for Materials Science, Research Center for Functional Materials, Japan, National Institute for Materials Science Tsukuba, National Institute for Materials Science, 1-1 Namiki, National Institute for Materials Science of Japan, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan, NIMS - National Institute for Material Science, Japan, Research Center for Functional Materials, National Institute for Material Science, Tsukuba, Ibaraki, 305-0044, Japan., National Institute for Material Science, Tsukuba, National Institute for Materials Science, Tsukuba, Ibaraki 305-0044, Japan, National Institute for Materials Science (NIMS), National Institute for Materials Science, Research Center for Functional Materials, Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan, National Institute of Material Science, Kyoto Univ, National Institute for Materials Science,1-1 Namiki, Tsukuba, 305-0044, Japan

  • Takashi Taniguchi

    National Institute for Materials Science, Tsukuba, Japan, National Institute for Materials Science, NIMS, Kyoto Univ, International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Ibaraki 305-0044, Japan., 3 National Institute for Materials Science, Tsukuba, Japan, National Institute for Materials Science; 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan, National Institute of Materials Science, Tsukuba, Japan, National Institute of Materials Science, Advanced Materials Laboratory, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan, National Institute for Materials Science (Japan), International Center for Materials Nanoarchitectonics, National Institute for Materials Science, International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan, Kyoto University, International Center for Materials Nanoarchitectonics, International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Japan, International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Japan, International Center for Materials Nanoarchitectonics, National Institute for MaterialsScience, 1-1 Namiki, Tsukuba 305-0044, Japan, National Institute for Material Science, Japan, National Institute for Material Science, National Institute of Material Sciences, Japan, NIMS, Tsukuba, 2National Institute for Materials Science, Namiki 1-1, Ibaraki 305-0044, Japan., National Institute of Materials Science, Tsukuba, Ibaraki 305-0044, Japan, National Institute for Materials Science, Japan, International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science, 1-1 Namiki Tsukuba, Ibaraki 305-0044, Japan., NIMS, Japan, National Institute for Materials Science (NIMS), NIMS. Japan, International Center for Material Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Japan, International Center for Material Nanoarchitectonics, National Institute for Materials Science, National Institute for Materials Science Tsukuba, National Institute for Materials Science, 1-1 Namiki, National Institute for Materials Science of Japan, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan, NIMS - National Institute for Material Science, Japan, International Center for Materials Nanoarchitectonics, National Institute for Material Science, Tsukuba, Ibaraki 305-0044, Japan., National Institute for Material Science, Tsukuba, National Institute for Materials Science, International Center for Materials Nanoarchitectonics, International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan, National Institute of Material Science, National Institute for Materials Science,1-1 Namiki, Tsukuba, 305-0044, Japan

  • Eva Y Andrei

    Rutgers University, Rutgers University, Department of Physics and Astronomy, 136 Frelinghuysen Rd, Piscataway, 08854, New Jersey, USA