We show that free-carrier (Drude) absorption of both polarized and unpolarized terahertz radiation in quantum well (QW) structures causes an electric photocurrent in the presence of an in-plane magnetic field. Experimental and theoretical analysis evidences that the observed photocurrents are spin-dependent and related to the gyrotropy of the QWs. Microscopic models for the photogalvanic effects in QWs based on asymmetry of photoexcitation and relaxation processes are proposed. In most of the investigated structures the observed magneto-induced photocurrents are caused by spin-dependent relaxation of non-equilibrium carriers.
@article{arxiv.cond-mat/0502191,
title = {Magneto-Gyrotropic Photogalvanic Effects in Semiconductor Quantum Wells},
author = {V. V. Bel'kov and S. D. Ganichev and E. L. Ivchenko and S. A. Tarasenko and W. Weber and S. Giglberger and M. Olteanu and H. -P. Tranitz and S. N. Danilov and Petra Schneider and W. Wegscheider and D. Weiss and W. Prettl},
journal= {arXiv preprint arXiv:cond-mat/0502191},
year = {2009}
}