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

Abstract
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.

Citation
Valley-dependent spin-orbit torques in two-dimensional hexagonal crystals 2016, 93 (3) Physical Review B

Publisher
American Physical Society (APS)

Journal
Physical Review B

DOI
10.1103/PhysRevB.93.035417

arXiv
1509.08060

Additional Links
http://link.aps.org/doi/10.1103/PhysRevB.93.035417

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