Berlin 2008 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 25: Spin controlled transport I

HL 25.2: Vortrag

Dienstag, 26. Februar 2008, 14:30–14:45, EW 202

Magneto-photogalvanic effect in (110) GaAs semiconductor quantum wells — •Peter Olbrich¹, Vasily V. Bel’kov^1,2, Dieter Schuh¹, Werner Wegscheider¹, Wilhelm Prettl¹, and Sergey D. Ganichev¹ — ¹Terahertz Center, University of Regensburg, 93040, Regensburg, Germany — ²A.F. Ioffe Physico-Technical Institute, Russian Academy of Sciences, 194021 St. Petersburg, Russia

We report on the observation of a magneto-photogalvanic effect (MPGE) [1] in (110)-grown GaAs semiconductor quantum wells. The MPGE so far has been demonstrated only in (001)-grown GaAs, InAs, SiGe and GaN quantum wells where its microscopic origin is the zero-bias spin separation [2]. The latter is caused by spin-dependent scattering of electrons due to a linear-in-k terms in the scattering matrix elements. Here we provide experimental and theoretical analysis of the MPGE current in (110)-grown GaAs showing that it is driven by asymmetric processes in excitation and relaxation of a Drude-like heated electron gas and reflects the contribution of structure inversion asymmetry. The results agree with the phenomenological description based on the symmetry. We demonstrate that the MPGE due to an in-plane magnetic field is only observed for asymmetric structures and vanishes if QWs are symmetric. Therefore it is an ideal tool to probe the symmetry of (110)-grown quantum wells, which is of importance to achieve long spin relaxation times.
V.V. Bel’kov et al., J. Phys.: Cond. Mat. 17, 3405 (2005).
S.D. Ganichev et al., Nature Physics (London) 2, 609 (2006).