Quantum kinetics of the coupled carrier‐phonon system in photoexcited semiconductors

A quantum kinetic analysis of the coupled carrier–LO‐phonon dynamics in photoexcited semiconductors is presented. The emission of phonons leads to the build‐up of a substantial nonequilibrium phonon distribution which is responsible for a reduced energy relaxation and an increased dephasing with increasing carrier density. Deviations from the semiclassical case are particularly pronounced at small phonon wave vectors, which cannot be reached by classical scattering processes. It turns out that the damping as introduced usually in quantum kinetic calculations leads to a violation of the conservation of the total energy.