Strain Control of Topological Edge Currents in a Chern Insulator

A hallmark of topological systems is the robustness of invariants to external perturbation. However, this quality presents the challenge of being able to externally switch between topological states. Here we present a DFT study which demonstrates that uniaxial strain can be used to tune topology in a Chern insulator. We work with a monolayer sample of the Janus material MnBi2Te2S2 which has a Chern number of two under zero strain. We show that an experimentally realistic value of applied tension can uninvert the topological band gap and reduce the Chern number to zero, thus enabling strain control of topology. Finally, we propose a topological relay switch device architecture which uses strain to control the flow of non-dissipative edge currents.