We study the commensuration torques and layer sliding energetics of alternating twist trilayer graphene (t3G) and twisted bilayer graphene on hexagonal boron nitride (t2G/BN) that have two superposed moire interfaces. Lattice relaxations for typical graphene twist angles of ∼1∘ in t3G or t2G/BN are found to break the out-of-plane layer mirror symmetry, give rise to layer rotation energy local minima dips of the order of ∼10−1 meV/atom at double moire alignment angles, and have sliding energy landscape minima between top-bottom layers of comparable magnitude. Moire superlubricity is restored for twist angles as small as ∼0.03∘ away from alignment resulting in suppression of sliding energies by several orders of magnitude of typically ∼10−4 meV/atom, hence indicating the precedence of rotation over sliding in the double moire commensuration process.
@article{arxiv.2301.04105,
title = {Commensuration torques and lubricity in double moire systems},
author = {Nicolas Leconte and Youngju Park and Jiaqi An and Jeil Jung},
journal= {arXiv preprint arXiv:2301.04105},
year = {2023}
}