Collective Modes of Photoexcited Electron-Hole Plasmas in GaAs

Abstract

Light scattering spectra of photoexcited electron-hole plasmas in GaAs show features due to the multicomponent nature of the plasma, and also specific to the presence of holes. At low energies, \ensuremath{\sim}5 meV, we observe a Landau-damped acoustic plasma mode. At higher energies inter-valence-band transitions of the photoexcited holes modify the spectra of coupled optic-plasmon-LO-phonon modes.