Dirac spin-orbit torques and charge pumping at the surface of topological insulators
KAUST DepartmentPhysical Sciences and Engineering (PSE) Division
Computer, Electrical and Mathematical Sciences and Engineering (CEMSE) Division
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AbstractWe address the nature of spin-orbit torques at the magnetic surfaces of topological insulators using the linear-response theory. We find that the so-called Dirac torques in such systems possess a different symmetry compared to their Rashba counterpart, as well as a high anisotropy as a function of the magnetization direction. In particular, the damping torque vanishes when the magnetization lies in the plane of the topological-insulator surface. We also show that the Onsager reciprocal of the spin-orbit torque, the charge pumping, induces an enhanced anisotropic damping. Via a macrospin model, we numerically demonstrate that these features have important consequences in terms of magnetization switching.
CitationNdiaye PB, Akosa CA, Fischer MH, Vaezi A, Kim E-A, et al. (2017) Dirac spin-orbit torques and charge pumping at the surface of topological insulators. Physical Review B 96. Available: http://dx.doi.org/10.1103/PhysRevB.96.014408.
SponsorsP.B.N. and A.M. were supported by the King Abdullah University of Science and Technology (KAUST). P.B.N. thanks Z. T. Ndiaye for the fruitful discussions and valuable technical support, and A.M. acknowledges inspiring discussions with H. Yang, E. Y. Tsymbal, and J. Zhang. E.-A. K. was supported by NSF CAREER Award No. DMR-0955822 and by the Cornell Center for Materials Research with funding from the NSF MRSEC program (Grant No. DMR-1120296). M.H.F. acknowledges support from the Swiss Society of Friends of the Weizmann Institute of Science.
PublisherAmerican Physical Society (APS)
JournalPhysical Review B