Quantum Anomalous Hall Effect in Graphene from Rashba and Exchange Effects

TL;DR

This paper demonstrates that by combining Rashba spin-orbit coupling and an exchange field, a quantum anomalous Hall effect can be realized in graphene, supported by theoretical calculations and first principles simulations.

Contribution

It introduces a novel way to induce quantum anomalous Hall effect in graphene through Rashba and exchange effects, supported by both theoretical and first principles approaches.

Findings

Bulk energy gap can be opened in graphene with Rashba and exchange effects.

Non-zero Chern number indicates topologically non-trivial phase.

Gapless edge states are demonstrated in the system.

Abstract

We investigate the possibility of realizing quantum anomalous Hall effect in graphene. We show that a bulk energy gap can be opened in the presence of both Rashba spin-orbit coupling and an exchange field. We calculate the Berry curvature distribution and find a non-zero Chern number for the valence bands and demonstrate the existence of gapless edge states. Inspired by this finding, we also study, by first principles method, a concrete example of graphene with Fe atoms adsorbed on top, obtaining the same result.