title: Direct comparison of current-induced spin polarization in topological insulator Bi2Se3and InAs Rashba states.
abstract: Three-dimensional topological insulators (TIs) exhibit time-reversal symmetry protected, linearly dispersing Dirac surface states with spin-momentum locking. Band bending at the TI surface may also lead to coexisting trivial two-dimensional electron gas (2DEG) states with parabolic energy dispersion. A bias current is expected to generate spin polarization in both systems, although with different magnitude and sign. Here we compare spin potentiometric measurements of bias current-generated spin polarization in Bi2Se3(111) where Dirac surface states coexist with trivial 2DEG states, and in InAs(001) where only trivial 2DEG states are present. We observe spin polarization arising from spin-momentum locking in both cases, with opposite signs of the measured spin voltage. We present a model based on spin dependent electrochemical potentials to directly derive the sign expected for the Dirac surface states, and show that the dominant contribution to the current-generated spin polarization in the TI is from the Dirac surface states.
authors.affiliation: Materials Science and Technology Division, Naval Research Laboratory, Washington, District of Columbia 20375, USA.
authors.forename: C H
authors.initials: CH
authors.lastname: Li
authors.affiliation: Materials Science and Technology Division, Naval Research Laboratory, Washington, District of Columbia 20375, USA.
authors.forename: O M J
authors.initials: OM
authors.lastname: van 't Erve
authors.affiliation: Department of Physics, University of Wisconsin, Milwaukee, Wisconsin 53211, USA.
authors.forename: S
authors.initials: S
authors.lastname: Rajput
authors.affiliation: Department of Physics, University of Wisconsin, Milwaukee, Wisconsin 53211, USA.|Department of Physics and Astronomy, West Virginia University, Morgantown, West Virginia 26506, USA.
authors.forename: L
authors.initials: L
authors.lastname: Li
authors.affiliation: Materials Science and Technology Division, Naval Research Laboratory, Washington, District of Columbia 20375, USA.
authors.forename: B T
authors.initials: BT
authors.lastname: Jonker