Superconductivity of the Two-Dimensional Penson-Kolb Model

Abstract

Two-dimensional (d = 2) Penson-Kolb model, i.e. the tight-binding model with the pair-hopping (intersite charge exchange) interaction, is considered and the effects of phase fluctuations on the s-wave superconductivity ofthis system are discussed within the Kosterlitz-Thouless scenario. The London penetration depth A at T = 0, the Kosterlitz-Thouless critical temperature T c , and the Hartree-Fock approximation critical temperature Tp are determined as a function of particle concentration and interaction. The Uemura type plots (T c vs. λ - 2 (0)) are derived. Beyond weak coupling and for low concentrations they show the existence of universal scaling: T c ∼ 1/λ 2 (0), as it was previously found for the attractive Hubbard model and for the models with intersite electron pairing.