Carrier Dynamics in the Quantum Kinetic Regime

Abstract

We present a study of carrier dynamics in GaAs during and just after creation by ultrashort laser pulses. We observe a quasi-instantaneous spread of the carrier population in momentum-energy space. Attempts to fit the scattering rates in the relaxation time approximation result in parameters outside the range of validity of the theory. We interpret this as a failure of the Boltzmann kinetic approach in the quantum kinetic regime.