Electron-phonon interaction and phonon dynamics in one-dimensional conductors

Abstract

We present results of a theoretical study of the influence of electron-electron and electron-phonon interactions, particularly backscattering, in one-dimensional metals. Particular attention is paid to the effects of the finite phonon frequency. We compute effective interaction constants and renormalized velocities for charge and spin excitations, as well as energy-gap parameters, where appropriate. We find that electron-phonon backscattering significantly enhances the tendency to form a charge-density-wave state and strongly decreases the velocity of the collective charge and spin fluctuations. We extend a previously developed approach which allows one to treat electron-electron and electron-phonon interactions on an equal footing to the relevant case where the spin degrees of freedom of the electrons are taken into account. It is based on both a weak-coupling–high-frequency and a strong-coupling–low-frequency limit which agree well in intermediate cases.