Triangular antiferromagnetism on the honeycomb lattice of twisted bilayer graphene

ORAL

Abstract

We present the electronic band structures of states with the same symmetry as the three-sublattice planar antiferromagnetic order of the triangular lattice. Such states can also be defined on the honeycomb lattice provided the spin density waves lie on the bonds. We identify cases which are consistent with observations on twisted bilayer graphene: a correlated insulator with an energy gap, yielding a single doubly-degenerate Fermi surface upon hole doping. We also discuss extensions to metallic states which preserve spin rotation invariance, with fluctuating spin density waves and bulk Z2 topological order.

*This research was supported by the NSF under Grant DMR-1664842. Research at Perimeter Institute is supported by the Government of Canada through Industry Canada and by the Province of Ontario through the Ministry of Research and Innovation. SS also acknowledges support from Cenovus Energy at Perimeter Institute.
MS acknowledges support from the German National Academy of Sciences Leopoldina through grant LPDS 2016-12.

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Presenters

  • Alexandra Thomson

    • Caltech

Authors

  • Alexandra Thomson

    • Caltech

  • Subir Sachdev

    • Department of Physics, Harvard University
    • Harvard University
    • Harvard Univeristy

  • Shubhayu Chatterjee

    • Department of Physics, University of California, Berkeley
    • UC Berkeley
    • Physics, University of California Berkeley

  • Mathias Scheurer

    • Department of Physics, Harvard University
    • Harvard University