Local and regular plasma oscillations in bulk donor type semiconductors

Abstract

Restoring force acts on the electronic cloud of the outer electrons of a neutral or charged impurity atom when it is shifted relative to the inner charged core. Because of this the dipole oscillation arises, which influences considerably the dispersion law of the plasma oscillation in bulk donor semiconductors. Assuming that only one transition of the outer electron from the ground state to the first excited state is essential, the dispersion law is calculated. It is shown that calculated dispersion law consists of two separate branches, one of them originates from the regular plasma oscillation of the free electrons of a conductivity band, and the other one stems from the local oscillation of the outer electrons bounded to the impurity atoms.