QUANTUM KINETIC INFLUENCES ON ELECTRON-PHONON SCATTERING IN SEMICONDUCTORS

The dynamics of photoexcited electrons in GaAs due to LO phonon emissi on is investigated, On an ultrafast timescale energy conservation is s een to be violated and non-Markovian memory effects are observed. init ially, the phonon replica are substantially broadened with respect to the unrelaxed excitation peak. As time proceeds, quantum interference becomes operative resulting in a narrowing of the maxima to the shape expected in the semiclassical limit. The timescale for these phenomena is given by the LO oscillation period. Quantum kinetic simulations ba sed on a simplified model that allows an exact treatment of the memory effects agree with our experimental data.