Electron-phonon interaction and coupled phonon--plasmon modes

TL;DR

This paper develops a theoretical framework for Raman scattering in metals and doped semiconductors, accounting for electron-phonon interactions, Coulomb screening, and carrier effects, with calculations across different carrier concentrations.

Contribution

It introduces a comprehensive model incorporating Coulomb screening and deformation interactions, using a semiclassical dielectric function instead of Lindhard-Mermin, for better understanding of coupled phonon-plasmon modes.

Findings

Renormalized phonon frequencies due to carrier interactions

Dependence of Raman scattering on carrier concentration

Effect of electron-phonon coupling on optic mode coupling constants

Abstract

The theory of Raman scattering by the electron--phonon coupled system in metals and heavily doped semiconductors is developed taking into account the Coulomb screening and the electron--phonon deformation interaction. The Boltzmann equation for carriers is applied. Phonon frequencies and optic coupling constants are renormalized due to interactions with carriers. The $k-$dependent semiclassical dielectric function is involved instead of the Lindhard-Mermin expression. The results of calculations are presented for various values of carrier concentration and electron-phonon coupling constant.