Optical electron spin pumping in n-doped quantum wells

Abstract

A theoretical model for optical spin pumping of electrons in a quantum well with lowintrinsic electron density is presented. A system of electrons under continuous-waveillumination by circularly polarized light tuned to the electron–trion resonance isconsidered. The simultaneous off-resonant creation of excitons is also taken into account.The spin flip of trions and their radiative decay as the basic processes which allow theelectronic spin pumping, as well as other processes, such as the formation of trions fromexcitons and electrons, are accounted for in the appropriate kinetic equations.The results obtained for CdTe and GaAs quantum wells indicate that significantelectron spin polarization can be achieved in a time range of a few nanoseconds.