Microscopic Analysis of the Coherent Optical Generation and the Decay of Charge and Spin Currents in Semiconductor Heterostructures

The coherent optical injection and temporal decay of spin and charge currents in semiconductor heterostructures is described microscopically, including excitonic effects, many-body Coulomb correlations, and the carrier LO-phonon coupling on the second-order Born-Markov level, as well as nonperturbative light-field-induced intraband and interband excitations. A nonmonotonic dependence of the currents on the intensities of the laser beams is predicted. Enhanced damping of the spin current relative to the charge current is obtained as a consequence of Coulomb scattering.