We show that recently reported [5] unusual hardening of optical phonons renormalized by the electron-phonon interaction [5] is due to the neglect of screening effects. When the electron-ion interaction is properly screened optical phonons soften in three dimension. It is important that for shortwavelength optical phonons screening is static while for long-wavelength optical phonons screening is...

We establish a unified model dealing with the transport of electron and phonon in double heterojunction structures with the coexistence of three nonequilibrium processes: (1) nonequilibrium among electrons, (2) nonequilibrium among phonons, and (3) nonequilibrium between electrons and phonons. Using this model, we investigate the energy conversion efficiency based on concurrent thermoelectric a...

The aim of this work is to describe the behavior of a device capable to generate high frequency (∼ THz) acoustic phonons. This device consists in a GaAs-AlGaAs double barrier heterostructure that, when an external bias is applied, produces a high rate of longitudinal optical LO phonons. These LO phonons are confined and they decay by stimulated emission of a pair of secondary longitudinal optic...

We have previously demonstrated that optical phonons and polaritons in simple compound semiconductors, e.g. , GaP, possess dephasing times in the picosecond and femtosecond time scales. ' In high-purity materials the source of the dephasing is dominated by three-particle anharmonic interactions. Others have demonstrated that longitudinal acoustic (LA) and transverse acoustic (TA) phonons decay ...