Spin-photocurrent in p-SiGe quantum wells under terahertz laser irradiation

Vassilij Belkov, Sergey Ganichev, Petra Schneider, D. Schowalter, Ulrich Rössler, Wilhelm Prettl, Eougenious Ivchenko, Richard Neumann, K. Brunner, Gerhard Abstreiter
A detailed study of the circular photogalvanic effect (CPGE) in SiGe structures is presented. It is shown that the CPGE becomes possible because of the built-in asymmetry of quantum wells (QWs) in compositionally stepped samples and in asymmetrically doped structures. The photocurrent arises due to optical spin orientation of free carriers in QWs with spin splitting in k-space. It is shown that the effect can be applied to probe the macroscopic in-plane symmetry of low dimensional structures
more » ... allowing to conclude on Rashba or Dresselhaus terms in the Hamiltonian.
doi:10.5283/epub.2172 fatcat:qnm5ihahkreclf52fndqx3rbey