Ganichev, Sergey and Danilov, Sergey and Belkov, Vassilij and Ivchenko, Eougenious and Ketterl, Hermann and Wegscheider, Werner and Vorobjev, L. E. and Bichler, Max and Prettl, Wilhelm
Nonlinear photogalvanic effect induced by monopolar spin orientation of holes in QWs.
Physica E Low-dimensional Systems and Nanostructures 10 (1-3), pp. 52-56.
We report on the first observation of the circular photogalvanic effect (CPGE) induced by optical monopolar spin orientation of holes in p-doped quantum-well structures. It is shown that monopolar optical spin orientation of free carriers causes an electric current which reverses its direction upon changing from left to right circularly polarized radiation. The effect has been observed in (0 0 1)- and (3 1 1)A-oriented p-GaAs/AlGaAs quantum wells at normal incidence of far-infrared radiation. The photocurrent is proportional to the light intensity at low power levels and gradually saturates with increasing intensity. The CPGE can be utilized to investigate separately spin polarization of electrons and holes and to determine spin-relaxation times.