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Experimental Observation of Tunable Chern insulator and Ferromagnetism in ABC-Trilayer Graphene on hBN Moiré Superlattice

ORAL

Abstract

Haldane theorized that Chern insulators with integer QH effects could appear in lattice models with complex hopping parameters even at zero magnetic field. The ABC-trilayer graphene/hexagonal boron nitride (TLG/hBN) moiré superlattice provides an attractive platform to explore Chern insulators because it features nearly flat moiré minibands with a valley-dependent electrically tunable Chern number. Here we report the experimental observation of a correlated Chern insulator in a TLG/hBN moiré superlattice. We show that reversing the direction of the applied vertical electric field switches TLG/hBN's moiré minibands between zero and finite Chern numbers, as revealed by dramatic changes in magneto-transport behavior. The Hall resistance is well quantized at h/2e2, i.e. C = 2, for B > 0.4 T. The correlated Chern insulator is ferromagnetic, exhibiting significant magnetic hysteresis and a large anomalous Hall signal at zero magnetic field. Our discovery of a C = 2 Chern insulator at zero magnetic field should open up exciting opportunities for discovering novel correlated topological states, possibly with novel topological excitations, in nearly flat and topologically nontrivial moiré minibands.

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Presenters

  • Guorui Chen

    University of California, Berkeley, UC Berkeley

Authors

  • Guorui Chen

    University of California, Berkeley, UC Berkeley

  • Aaron Sharpe

    Physics, Stanford University, Stanford Univ, Stanford

  • Eli J Fox

    Stanford Univ, Stanford

  • Yahui Zhang

    Harvard University, Department of Physics, Harvard University, MIT

  • Shaoxin Wang

    University of California, Berkeley

  • Lili Jiang

    University of California, Berkeley, Department of Physics, University of California, Berkeley

  • Bosai Lv

    Shanghai JiaoTong University

  • Hongyuan Li

    University of California, Berkeley, Department of Physics, University of California, Berkeley

  • 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

  • Zhiwen Shi

    Shanghai JiaoTong University, Shanghai Jiao Tong University

  • Senthil Todadri

    Department of Physics, Massachusetts Institute of Technology, MIT

  • David Goldhaber-Gordon

    Stanford Univ, Physics, Stanford University, Stanford, Department of Physics, Stanford University

  • Yuanbo Zhang

    Fudan University, Fudan Univ

  • Feng Wang

    University of California at Berkeley, University of California, Berkeley, UC Berkeley, Physics, University of California, Berkeley, University of California, Berkeley and MSD, LBNL, Department of Physics, University of California, Berkeley