Individual band with higher Chern numbers in double perovskite {001} monolayers

TL;DR

This paper presents a tight-binding model for double perovskite {001} monolayers that can host higher Chern number bands, tunable by magnetic fields, potentially enabling new quantum anomalous Hall states.

Contribution

It introduces a model demonstrating higher Chern numbers in double perovskite monolayers and shows how to tune between these phases with a magnetic field.

Findings

Higher Chern numbers (up to ±8) are possible in the model.

Tuning between topological phases is achievable with weak magnetic fields.

Potential realization of quantum anomalous Hall insulators with higher Chern numbers.

Abstract

We show a tight-binding model for double perovskite monolayers grown in the {001} crystallographic direction can exhibit higher Chern numbers for the lowest band of the model dispersion in the absence of an applied magnetic field, including $\pm2$, $\pm4$, $\pm6$, and $\pm8$, for model parameters and terms relevant to Sr$_2$CrWO$_6$ (SCWO). We further show it is possible to tune between these different topological phases by applying a weak in-plane magnetic field. These results may be important for experimentally realizing exotic band topologies -- and even quantum anomalous Hall insulators with higher Chern numbers -- based on this physics.