Commensurate and incommensurate double moir\'e interference in twisted trilayer graphene

TL;DR

This study investigates the electronic structures of twisted trilayer graphene with two independent twist angles, revealing how moiré interference, lattice relaxation, and angle disorder influence van Hove singularities and supermoiré patterns, guiding experimental exploration of flat bands.

Contribution

It introduces an atomistic approach combining tight-binding and molecular dynamics to analyze complex supermoiré patterns in twisted trilayer graphene with variable twist angles.

Findings

Lattice relaxation significantly affects van Hove singularities.

Moiré interference can create superstructures like Kagome lattices.

Small angle disorder suppresses van Hove singularities.

Abstract

Twisted graphene multi-layers have been recently demonstrated to share several correlation-driven behaviours with twisted bilayer graphene. In general, the van Hove singularities (VHSs) can be used as a proxy of the tendency for correlated behaviours. In this paper, we adopt an atomistic method by combining tight-binding method with the semi-classical molecular dynamics to investigate the electronic structures of twisted trilayer graphene (TTG) with two independent twist angles. The two independent twist angles can lead to the interference of the moir\'e patterns forming a variety of commensurate/incommensurate complex supermoir\'e patterns. In particular, the lattice relaxation, twist angle and angle disorder effects on the VHS are discussed. We find that the lattice relaxation significantly influence the position and magnitude of the VHSs. In the supermoir\'e TTG, the moir\'e interference provides constructive or destructive effects depending on the relative twist angle. By modulating the two independent twist angles, novel superstructures, for instance, the Kagome-like lattice, could constructed via the moir\'e pattern. Moreover, we demonstrate that a slight change in twist angles (angle disorder) provides a significant suppression of the peak of the VHSs. Apart from the moir\'e length, the evolution of the VHSs and the LDOS mapping in real space could be used to identify the twist angles in the complicated TTG. In practice, our work could provide a guide for exploring the flat band behaviours in the supermoir\'e TTG experimentally.