Monopolar Optical Orientation of Electronic Spins in Semiconductors

Tarasenko, S. A.; Ivchenko, E. L.; Bel'kov, V. V.; Ganichev, S. D.; Schowalter, D.; Schneider, Petra; Sollinger, M.; Prettl, W.; Ustinov, V. M.; Zhukov, A. E.; Vorobjev, L. E.

Monopolar Optical Orientation of Electronic Spins in Semiconductors

Authors

Description

It is shown that absorption of circularly polarized infrared radiation due to intraband (Drude-like) transitions in n-type bulk semiconductors and due to intra-subband or inter-subband transitions in quantum well (QW) structures results in a monopolar spin orientation of free electrons. Spin polarization in zinc-blende-structure based QWs is demonstrated by the observation of the spin-galvanic and the circular photogalvanic effects. The monopolar spin orientation in n-type materials is shown to be possible if an admixture of valence band states to the conduction band wave function and the spin-orbit splitting of the valence band are taken into account.