Dielectric function and collective plasmon modes of a quasi-two-dimensional finite confining potential semiconductor quantum well

We have calculated the dielectric function for the quasi-two-dimensional (Q2D) finite confining potential quantum well (QW) electron gas using a self-consistent approach. Taking into account the influence of strong discontinuous dielectric constants and the effective masses mismatch across the interfaces the dielectric function analytic expression is derived in the rectangular finite potential barrier QW for the first time. The initial deviations from the results in the absence of these mismatches are established. By means of exactly calculated dielectric function, the unretarded plasmon dispersion relation is determined and a comparison with the respective asymptotic expressions of finite and infinite confining models is presented. The observation possibilities of Q2D plasmon modes already at low and several low densities on the base of realistic EuS/PbS/EuS QW are demonstrated numerically.