High temperature spin Hall effect in topological insulator

Applications of spin–orbit torque (SOT) spintronic devices to automobile or space vehicles require a spin Hall material with high performance at high temperature (>120 °C). However, the spin Hall effect has been studied so far in many materials mostly from cryogenic to room temperature. Here, we studied the spin Hall effect in BiSb topological insulator up to 125 °C. Although the effective spin Hall angle θ SH eff of BiSb monotonically decreases with increasing temperature, BiSb maintains a large θ SH eff of 4.9 even at 125 °C, demonstrating the capability of BiSb for high temperature applications. Furthermore, the temperature-dependence of the spin Hall conductivity indicates that the topological surface states are the origin of the giant spin Hall effect in BiSb.