Under oblique incidence of circularly polarized infrared radiation the spin-galvanic effect has been unambiguously observed in (001)-grown n-type GaAs quantum well (QW) structures in the absence of any external magnetic field. Resonant inter-subband transitions have been obtained making use of the tunability of the free-electron laser FELIX. It is shown that a helicity dependent photocurrent along one of the <110> axes is predominantly contributed by the spin-galvanic effect while that along the perpendicular in-plane axis is mainly due to the circular photogalvanic effect. This strong non-equivalence of the [110] and [11ˉ0] directions is determined by the interplay between bulk and structural inversion asymmetries. A microscopic theory of the spin-galvanic effect for direct inter-subband optical transitions has been developed being in good agreement with experimental findings.
@article{arxiv.cond-mat/0303193,
title = {Spin-galvanic effect due to optical spin orientation},
author = {S. D. Ganichev and Petra Schneider and V. V. Bel'kov and E. L. Ivchenko and S. A. Tarasenko and W. Wegscheider and D. Weiss and D. Schuh and B. N. Murdin and P. J. Phillips and C. R. Pidgeon and D. G. Clarke and M. Merrick and P. Murzyn and E. V. Beregulin and W. Prettl},
journal= {arXiv preprint arXiv:cond-mat/0303193},
year = {2007}
}