Coupled plasmon–LO-phonon excitations in semiconductor superlattices

Abstract

The intrasubband collective excitations in semiconductor superlattice systems have been investigated within a simple model theory with the use of a two-dimensional δ function for the charge-density profiles. In particular, the coupling of the plasmons to the LO (longitudinal optical) phonons is accounted for. The coupling effect modifies the plasmon dispersion and generates additional (bulk and surface) modes above ωL (LO-phonon frequency). This can give rise to some interesting observable effects, particularly because the interaction effects on the physical properties are usually enhanced in systems of lower dimensionality.