Lattice Model For The Quantum Anomalous Hall Effect in Moir\'e Graphene

TL;DR

This paper introduces a lattice mean-field model for the quantum anomalous Hall effect in moiré graphene, demonstrating chiral edge states and domain wall structures relevant to experimental observations.

Contribution

It provides a simple lattice model capturing the quantum anomalous Hall effect in moiré graphene, linking theoretical predictions with experimental possibilities.

Findings

Presence of thick chiral edge states with moiré-scale localization

Demonstration of domain walls between opposite Chern insulators

Model applicable to experimental imaging and manipulation of edge states

Abstract

Inspired by experiments on magic angle twisted bilayer graphene, we present a lattice mean-field model for the quantum anomalous Hall effect in a moir\'e setting. Our hopping model thus provides a simple route to a moir\'e Chern insulator in commensurately twisted models. We present a study of our model in the ribbon geometry, in which we demonstrate the presence of thick chiral edge states that have a transverse localization that scales with the moir\'e lattice spacing. We also study the electronic structure of a domain wall between opposite Chern insulators. Our model and results are relevant to experiments that will image or manipulate the moir\'e quantum anomalous Hall edge states.