Gate-Tunable Topological Flat Bands in Trilayer Graphene-Boron Nitride Moiré Superlattices

ORAL

Abstract

We investigate the electronic structure of the flat bands induced by moiré superlattices and electric fields in nearly aligned ABC trilayer graphene-boron nitride interfaces where Coulomb effects can lead to correlated gapped phases. Our calculations indicate that valley-spin resolved isolated superlattice flat bands that carry a finite Chern number C = 3 proportional to layer number can appear near charge neutrality for appropriate perpendicular electric fields and twist angles. When the degeneracy of the bands is lifted by Coulomb interactions these topological bands can lead to anomalous quantum Hall phases that embody orbital and spin magnetism. Narrow bandwidths of ∼10 meV achievable for a continuous range of twist angles θ ≤ 0.6° with moderate interlayer potential differences of ∼50 meV make the TLG/BN systems a promising platform for the study of electric-field tunable Coulomb interaction driven spontaneous Hall phases.

Reference: arXiv:1806.00462

*We acknowledge support from Samsung through SSTF-BA1802-06, and the Korean NRF through NRF-2017R1D1A1B03035932 for B.L.C. and NRF-2016R1A2B4010105 for JJ. We also acknowledge ARO MURI award (W911NF- 15-1-0447). and support from National Key Research Program of China (2016YFA0300703) for Y.Z.

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Presenters

  • Bheema Lingam Chittari

    • University of Seoul
    • Department of Physics, University of Seoul, Seoul 02504, Korea

Authors

  • Bheema Lingam Chittari

    • University of Seoul
    • Department of Physics, University of Seoul, Seoul 02504, Korea

  • Guorui Chen

    • Physics, UC Berkeley
    • Department of Physics, University of California at Berkeley, Berkeley, CA 94709, USA

  • Yuanbo Zhang

    • Fudan University
    • State Key Laboratory of Surface Physics and Department of Physics, Fudan University
    • Institute for Nanoelectronic Devices and Quantum Computing, Fudan University, Shanghai 200433, China
    • Dept. of Physics, Fudan University
    • Physics Department, Fudan University

  • Feng Wang

    • University of California - Berkeley
    • University of California, Berkeley
    • Physics, UC Berkeley
    • Department of Physics, University of California at Berkeley, Berkeley, CA 94709, USA
    • University of California at Berkeley
    • Lawrence Berkeley National Laboratory and UC Berkeley
    • UC Berkeley
    • Physics, University of California, Berkeley

  • Jeil Jung

    • University of Seoul
    • Department of Physics, University of Seoul, Seoul 02504, Korea
    • Department of Physics, University of Seoul