Berlin 2012 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 32: Transport Properties I (mainly Spin Physics and Magnetic Fields)
HL 32.12: Talk
Tuesday, March 27, 2012, 13:00–13:15, EW 203
Realization of a persistent spin helix in InGaAs/InAlAs quantum wells — •V. Lechner1, M. Kohda2, Y. Kunihashi2, J. Nitta2, L.E. Golub3, V.V. Bel’kov3, K. Richter1, D. Weiss1, C. Schönhuber1, I. Caspers1, P. Olbrich1, and S.D. Ganichev1 — 1University of Regensburg, Germany — 2Tohoku University, Sendai, Japan — 3Ioffe Institute, St. Petersburg, Russia
Here we report on the realization of the persistent spin helix in InAs quantum wells (QWs) hosting a two dimensional electron gas. The sample consists of a 4 nm wide In0.53Ga0.47As QW with In0.52Al0.48As barriers and was grown strain free on a (001)-oriented InP substrate. A persistent spin helix can emerge if the k-linear Rashba and Dresselhaus spin orbit interactions are of equal strength (α = β). The realization of this condition has been proved by magneto-transport measurements, where the transition from weak anti-localization to weak localization and back to weak anti-localization was observed under a variation of the gate voltage. This result was confirmed by measurements of the anisotropy of THz radiation induced photocurrents, the circular photogalvanic and the spin-galvanic effect, applying the methods of [1]. Via these methods the relative strength of α and β was estimated in a wide temperature range from 5 K up to room temperature. We also analyzed the importance of the k-cubic Dresselhaus terms.
[1] S. Giglberger et al., Phys. Rev. B 75, 035327 (2007).