Dissipationless transport by design in ultrathin magnetic topological insulator films

Abstract

Magnetic topological insulators (MTIs) are among the prominent platforms for the next generation of high-speed and low-power spintronic devices. However, unlike their non-magnetic counterparts, where the surface spin-momentum locking prevents electrons from being scattered by non-magnetic impurities and results in a dissipationless electronic flow, magnetic impurities in MTIs cause dissipation by exerting magnetic torque on the electron spin. Decreasing this resistance is desired to reduce energy consumption and optimize performance of MTIs in envisaged applications. Here we reveal how electronic backscattering can be suppressed in a MTI thin film by external magnetic and/or electronic stimuli, to yield an entirely dissipationless spin-polarized charge transport. Our findings thus present an effective route to preserve spin coherence and enhance spin-current functionality in magnetic topological materials, suggesting design strategies for magneto-electronic and spintronic devices with strongly reduced energy consumption.