Persistent charge and spin currents in the 1D Holstein-Hubbard ring at half filling and at away from half filling by Bethe-ansatz approach

Abstract

The persistent charge and spin currents are studied by considering the Holstein-Hubbard model for one dimensional mesoscopic ring. Conventional Lang-Firsov transformation is used to eliminate the phonon coordinates and then the zero phonon state is applied to obtain the effective electronic Hamiltonian which is then treated exactly by the Bethe-Ansatz technique. The coupled transcendental equations that arise in this method are solved numerically and the persistent charge and spin currents are studied with respect to the on-site electron-electron Coulomb correlation (U), on-site electron-phonon interaction strength (g0) and inter-site electron-phonon interaction strength (g1) at half-filling and away from half-filling.