ELECTRON RELAXATION BY LO PHONONS IN QUANTUM WIRES - AN ADIABATIC APPROACH

The electron states of weakly-one-dimensional quantum wires are comput ed using the adiabatic approximation in the framework of the k . p the ory and the envelope-function approximation. The computed transition r ates of electrons from one confined state to any other, mediated by th e longitudinal optical (LO) phonons, are clearly ordered with respect to the quantum numbers of the states provided by the adiabatic approxi mation. The average single electron relaxation time from an excited le vel is shown to either increase or surprisingly decrease as a function of initial energy. Finally, the relaxation dynamics of an excited pop ulation of electrons is analyzed. We show that a fast phenomenological intrasubband thermalization, simultaneous to the LO phonon-mediated r elaxation, lowers the final average energy and may in some cases signi ficantly speed up the whole relaxation.