Plasmon-LO-phonon coupling effects on the drag rate in double quantum-well systems

Abstract

We study the Coulomb drag rate for electrons in a double-quantum-well structure taking into account the electron-optical phonon interactions. The full wave vector and frequency dependent random-phase approximation (RPA) at finite temperature is employed to describe the effective interlayer Coulomb interaction. The electron-electron and electron-optical phonon couplings are treated on an equal footing. The electron-phonon mediated interaction contribution is investigated for different layer separations and layer densities. We find that the drag rate at high temperatures (i.e., T ≥ 0.3 E F ) is dominated by the coupled plasmon-phonon of the system. Including the local-field effects in an approximate way we estimate the importance of intralayer correlations to be significant.