Enhanced spin Hall effect at high temperature in non-centrosymmetric silicide TaSi2 driven by Berry phase monopoles

Abstract

We demonstrate the concept of Berry phase monopole engineering of the spin Hall effect in non-centrosymmetric silicide TaSi2. We show that while the effective damping-like spin–orbit torque (SOT) efficiency θDLeff of TaSi2 is nearly unchanged from 62 to 288 K (−0.049 to −0.069), θDLeff suddenly increases at high temperatures and becomes nearly double (−0.12) at 346 K. The corresponding intrinsic spin Hall conductivity σDLeff significantly increases at high temperatures, which can be attributed to the increasing contribution from the four degenerate points near the Fermi level via thermal excitation. Our results provide a strategy to enhance θDLeff at high temperatures via Berry phase monopole engineering and pave the way for SOT spintronic devices working at high temperatures.