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Global phase diagram of twisted bilayer graphene above T<sub>C</sub>

ORAL

Abstract

We investigate the full doping and strain-dependent phase diagram (absent superconductivity) of magic-angle twisted bilayer graphene. Using comprehensive Hartree-Fock calculations, we show that at temperatures where superconductivity is absent the global phase structure can be understood based on the competition and coexistence between three types of intertwined orders: a fully symmetric phase, spatially uniform flavor-symmetry-breaking states, and an incommensurate Kekulé spiral (IKS) order. For small strain, the IKS phase, recently proposed as a candidate order at all non-zero integer fillings of the moiré unit cell, is found to be ubiquitous for non-integer doping as well. We demonstrate that the corresponding electronic compressibility and Fermi surface structure are consistent with the 'cascade' physics and Landau fans observed experimentally.

Publication: arXiv preprint arXiv:2109.09749

Presenters

  • Glenn Wagner

    Univ of Zurich

Authors

  • Glenn Wagner

    Univ of Zurich

  • Yves H Kwan

    University of Oxford

  • Nick Bultinck

    University of Oxford, Ghent University, University of Oxford

  • Steven H Simon

    University of Oxford

  • Siddharth A Parameswaran

    University of Oxford