Effect of Coulomb Interactions on the Peierls Instability

Abstract

The effect of electron-electron repulsion on the ground-state properties of one-dimensional electron-phonon systems is considered in the half-filled-band case. Two different electron-phonon models are studied, with use of a numerical simulation technique. For large phonon frequency, an on-site electron repulsion suppresses the Peierls distortion in both models, while for small phonon frequency, it enhances the dimerization in one model. The effect of a nearest-neighbor repulsion is always to enhance the ground-state dimerization.