Proximity induced quantum anomalous Hall effect in graphene/EuO hetero-structures

TL;DR

This paper models how EuO induces topologically non-trivial bands in graphene, leading to the quantum anomalous Hall effect through proximity effects, with potential implications for spintronics.

Contribution

It develops a model Hamiltonian based on ab initio calculations to describe proximity-induced effects in graphene/EuO heterostructures, identifying conditions for the quantum anomalous Hall effect.

Findings

Proximity exchange and inter-valley interactions are induced in graphene by EuO.

The model predicts topologically non-trivial bands with quantized Hall conductivity.

Conditions for realizing the quantum anomalous Hall effect are identified.

Abstract

In a heterostructure of graphene and the ferromagnetic insulator EuO, the Eu atoms induce proximity exchange and inter-valley interactions in the graphene layer. Constrained by the lattice symmetries, and guided by ab initio calculations, a model Hamiltonian is constructed that describes the low-energy bands. Band parameters such as proximity induced exchange splitting, spin orbit coupling, and inter-valley interaction are determined. Calculations of the Chern number identify the conditions under which the hetero-structures exhibit topologically non-trivial bands that give rise to the quantum anomalous Hall effect with a Hall conductivity of $\sigma_{xy} = 2 e^2/h$.