2016

Valley-dependent spin-orbit torques in two-dimensional hexagonal crystals

Valley-dependent spin-orbit torques in two-dimensional hexagonal crystals
H. Li, X. Wang, and A. Manchon
Phys. Rev. B 93, 035417 (2016)​
H. Li, X. Wang, A. Manchon
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2016
​We study spin-orbit torques in two-dimensional hexagonal crystals such as graphene, silicene, germanene, and stanene. The torque possesses two components, a fieldlike term due to inverse spin galvanic effect and an antidamping torque originating from Berry curvature in mixed spin-k space. In the presence of staggered potential and exchange field, the valley degeneracy can be lifted and we obtain a valley-dependent Berry curvature, leading to a tunable antidamping torque by controlling the valley degree of freedom. The valley imbalance can be as high as 100% by tuning the bias voltage or magnetization angle. These findings open new venues for the development of current-driven spin-orbit torques by structural design.​