Circular photogalvanic effect induced by monopolar spin orientation in p-GaAs/AlGaAs multiple-quantum wells

The circular photogalvanic effect (CPGE) has been observed in (100)-oriente d p-GaAs/AlGaAs quantum wells at normal incidence of far-infrared radiation . It is shown that monopolar optical spin orientation of free carriers caus es an electric current which reverses its direction upon changing from left to right circularly polarized radiation. CPGE at normal incidence and the occurrence of the linear photogalvanic effect indicate a reduced point symm etry of studied multilayered heterostructures. As proposed, CPGE can be uti lized to investigate separately spin polarization of electrons and holes an d the symmetry of quantum wells. (C) 2000 American Institute of Physics. [S 0003- 6951(00)05446-2].