Topological insulators for efficient spin-orbit torques

Abstract

Current-induced magnetic switching via spin-orbit torques has been extensively pursued for memory and logic applications with promising energy efficiency. Topological insulators are a group of materials with spin-momentum locked electronic states at the surface due to spin-orbit coupling, which can be harnessed to reach strong spin-orbit torques. In this paper, we summarize and compare the methods for calibrating the charge-spin conversion efficiency in topological insulators, with which topological insulators are identified as outstanding spin-orbit torque generators compared with the well-studied heavy metals. We then review the results of magnetic switching under reduced current density in topological insulator/ferromagnet heterostructures. Finally, we provide insights on current challenges as well as possible exploration directions in the emerging field of topological spintronics.