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  • Letter
  • Open Access

Kekulé spirals and charge transfer cascades in twisted symmetric trilayer graphene

Ziwei Wang1, Yves H. Kwan2, Glenn Wagner3, Nick Bultinck1,4, Steven H. Simon1, and S. A. Parameswaran1

  • 1Rudolf Peierls Centre for Theoretical Physics, Parks Road, Oxford OX1 3PU, United Kingdom
  • 2Princeton Center for Theoretical Science, Princeton University, Princeton, New Jersey 08544, USA
  • 3Department of Physics, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
  • 4Department of Physics, Ghent University, Krijgslaan 281, 9000 Gent, Belgium

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Phys. Rev. B 109, L201119 – Published 16 May, 2024

DOI: https://doi.org/10.1103/PhysRevB.109.L201119

Abstract

We study the phase diagram of magic-angle twisted symmetric trilayer graphene in the presence of uniaxial heterostrain and interlayer displacement field. For experimentally reasonable strain, our mean-field analysis finds robust Kekulé spiral order whose doping-dependent ordering vector is incommensurate with the moiré superlattice, consistent with recent scanning tunneling microscopy experiments, and paralleling the behavior of closely related twisted bilayer graphene (TBG) systems. Strikingly, we identify a possibility absent in TBG: the existence of commensurate Kekulé spiral order even at zero strain for experimentally realistic values of the interlayer potential in a trilayer. Our studies also reveal a complex pattern of charge transfer between weakly and strongly dispersive bands in strained trilayer samples as the density is tuned by electrostatic gating, that can be understood intuitively in terms of the “cascades” in the compressibility of magic-angle TBG.

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Phys. Rev. B 109, L201119– Published 16 May, 2024
  • Received 2 February 2024
  • Accepted 3 May 2024
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