title: Topological Surface States Originated Spin-Orbit Torques in Bi(2)Se(3).
abstract: The three dimensional topological insulator bismuth selenide (Bi(2)Se(3)) is expected to possess strong spin-orbit coupling and spin-textured topological surface states and, thus, exhibit a high charge to spin current conversion efficiency. We evaluate spin-orbit torques in Bi(2)Se(3)/Co(40)Fe(40)B(20) devices at different temperatures by spin torque ferromagnetic resonance measurements. As the temperature decreases, the spin-orbit torque ratio increases from ∼0.047 at 300 K to ∼0.42 below 50 K. Moreover, we observe a significant out-of-plane torque at low temperatures. Detailed analysis indicates that the origin of the observed spin-orbit torques is topological surface states in Bi(2)Se(3). Our results suggest that topological insulators with strong spin-orbit coupling could be promising candidates as highly efficient spin current sources for exploring the next generation of spintronic applications.
authors.affiliation: Department of Electrical and Computer Engineering, National University of Singapore, 117576 Singapore, Singapore.
authors.forename: Yi
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Electrical and Computer Engineering, National University of Singapore, 117576 Singapore, Singapore.
authors.forename: Praveen
authors.initials: P
authors.lastname: Deorani
authors.affiliation: Department of Electrical and Computer Engineering, National University of Singapore, 117576 Singapore, Singapore.
authors.forename: Karan
authors.initials: K
authors.lastname: Banerjee
authors.affiliation: Department of Physics and Astronomy, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, USA.
authors.forename: Nikesh
authors.initials: N
authors.lastname: Koirala
authors.affiliation: Department of Physics and Astronomy, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, USA.
authors.forename: Matthew
authors.initials: M
authors.lastname: Brahlek
authors.affiliation: Department of Physics and Astronomy, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, USA.
authors.forename: Seongshik
authors.initials: S
authors.lastname: Oh
authors.affiliation: Department of Electrical and Computer Engineering, National University of Singapore, 117576 Singapore, Singapore.
authors.forename: Hyunsoo
authors.initials: H
authors.lastname: Yang