paper

Supermoiré low-energy effective theory of twisted trilayer graphene

arXiv:2210.11507 · doi:10.1103/PhysRevB.107.125423

Abstract

Stacking three monolayers of graphene with a twist generally produces two moiré patterns. A moiré of moiré structure then emerges at larger distance where the three layers periodically realign. We devise here an effective low-energy theory to describe the spectrum at distances larger than the moiré lengthscale. In each valley of the underlying graphene, the theory comprises one Dirac cone at the point of the moiré Brillouin zone and two weakly gapped points at and . The velocities and small gaps exhibit a spatial dependence in the moiré-of-moiré unit cell, entailing a non-abelian connection potential which ensures gauge invariance. The resulting model is numerically solved and a fully connected spectrum is obtained, which is protected by the combination of time-reversal and twofold-rotation symmetries.

17 pages, 15 figures

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