Proximity effect in graphene-topological insulator heterostructures

TL;DR

This paper develops a continuum model to investigate how stacking graphene on a topological insulator enhances graphene's spin-orbit coupling, with tunability via twist angle or lattice mismatch.

Contribution

It introduces a novel continuum model for graphene-TI heterostructures considering both commensurate and incommensurate stacking configurations.

Findings

TI proximity strongly enhances graphene's spin-orbit coupling

Enhancement can be tuned by twist angle or lattice mismatch

Model applies to various stacking arrangements

Abstract

We formulate a continuum model to study the low-energy electronic structure of heterostructures formed by graphene on a strong three-dimensional topological insulator (TI) for the case of both commensurate and incommensurate stacking. The incommensurability can be due to a twist angle between graphene and the TI surface or a lattice mismatch between the two systems. We find that the proximity of the TI induces in graphene a strong enhancement of the spin-orbit coupling that can be tuned via the twist angle.