The polaron effects and relaxation of nonequilibrium electrons in the quasi-two-dimensional systems

The problem on weak-coupling polaron in the quasi-two-dimensional electron system is solved. Analytical expressions for polaron energy shift of the subband and polaron contribution to the effective electron mass with the arbitrary quantum well width are found. The expressions obtained give well-known values for two- and three-dimensional limit cases. The comparison of polaron contribution to the mass with the available experimental data is carried out. Energy relaxation processes of nonequilibrium quasi-two-dimensional electrons with the optic phonon emission are also considered. General analytical expressions for the frequencies of intra-subband and inter-subband transitions for the threshold electron energy are obtained. (author). 12 refs, 4 figs