Excitonic mechanism for superconductivity in a quasi-one-dimensional system

Abstract

The properties of a one-dimensional electron-exciton model are studied using weak- and strong-coupling perturbation theory, along with Monte Carlo simulations in the intermediate-coupling regime. We focus on the charge-density wave (CDW) and singlet-pairing susceptibilities, and determine their behavior as functions of the parameters in the Hamiltonian. We also discuss the properties of an array of weakly coupled chains. Our conclusions are that for a single chain it is possible, although difficult, to have pairing correlations dominate over CDW correlations. For an array of weakly coupled chains, however, it is highly unlikely that one would obtain a transition to a superconducting state.