Dielectric Screening, Polar Phonons, and Longitudinal Electronic Excitations of Quantum Well Double Heterostructures Application to Light Scattering from Charge Density Fluctuations

Abstract

Abstract The screened Coulomb potential and the inverse dielectric function of a quantum‐well double heterostructure (DHS) are expressed in terms of bulk dielectric functions. The spatial dispersion is fully taken into account. The polar LO‐phonon modes, longitudinal electronic modes, and coupled electron‐phonon modes of a DHS are derived from the poles of the inverse dielectric function. Emphasis is paid to phonon slab modes. The close relation between the screened Coulomb potential and the density‐density correlation function is used to calculate the Raman cross section for scattering from charge density fluctuations. In typical cases slab modes are essential for Raman spectra of DHSs and superlattices.