A Simple Heavy Fermion Model for Twisted Bilayer Graphene in Flux

ORAL

Abstract

The flat bands and large Coulomb scale of twisted bilayer graphene allow the low energy degrees of freedom to be written in terms of heavy fermions hybridizing with conduction electrons [1]. This work puts forward a simplified generalization of this model in flux, allowing for an analytical description of twisted bilayer graphene in magnetic field. We compare our results with a strong coupling Hofstadter calculation at rational flux. Using the recently developed gauge invariant formalism [2], we are able to reach numerically extremely small fluxes, allowing us to compare the two methods and confirm their agreement. Due to the simple nature of the heavy fermion model, we are able to give an intuitive interpretation of the spectrum of TBG in flux and provide wavefunctions for the dominant, strongly correlated Landau levels.

[1] Z.-D. Song and B. A. Bernevig, Phys. Rev. Lett. 129, 047601 (2022)

[2] J. Herzog-Arbeitman, A. Chew, and B. A. Bernevig, Phys. Rev. B 106, 085140 (2022)

*European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (grant agreement No. 101020833), the ONR Grant No. N00014-20-1-2303, the Schmidt Fund for Innovative Research, Simons Investigator Grant No. 404513, the Packard Foundation, the Gordon and Betty Moore Foundation through the EPiQS Initiative, Grant GBMF11070 and Grant No. GBMF8685 towards the Princeton theory program.

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Presenters

  • Aaron Chew

    • Princeton University

Authors

  • Aaron Chew

    • Princeton University

  • Jonah Herzog-Arbeitman

    • Princeton University

  • Oskar Vafek

    • Florida State University

  • Andrei B Bernevig

    • Princeton University