Dresden 2011 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 33: Spin-dependent Transport I
HL 33.5: Vortrag
Dienstag, 15. März 2011, 11:15–11:30, POT 251
Spin polarized photocurrents in InAs:Mn based quantum wells — •P. Olbrich1, C. Zoth1, C. Drexler1, V. Lechner1, I. Caspers1, V. Bel’kov2, S. Weishäupl1, D. Vogel1, U. Wurstbauer3, D. Schuh1, D. Weiss1, and S.D. Ganichev1 — 1Terahertz Center, Regensburg, Germany — 2Ioffe Institute, St. Petersburg, Russia — 3Columbia University, NY, USA
We report on the observation and investigation of terahertz (THz) radiation induced spin polarized currents in manganese doped InAs quantum well structures (QWs). The study is aimed to explore the spin-orbit interaction in this novel material system. The incorporation of Mn into an InAs QW leads to a 2D hole gas with interesting properties as both the g*-factor and Rashba type of spin-orbit coupling are large. Here, we demonstrate that in Mn-doped InAs QWs the absorption of THz radiation leads to pure spin currents, which we converted into a net electric current by means of an external in-plane magnetic field. Our results, in particular the dependence of the current on the magnetic field strength and temperature, have provided a feedback to the segregation of manganese. We show that as a result of this process only in systems with Mn introduced from the substrate side the spin-dependent scattering and Zeeman effect become enhanced. This result is supported by transport measurements of the longitudinal magnetoresistance. In addition, by applying photogalvanic effects we studied the anisotropy of the band spin splitting and provide the information on the ratio between the Rashba and Dresselhaus terms in InAs:Mn QWs of various designs.