Acta Physica Polonica A
Superconductivity of the Two-Dimensional Penson-Kolb Model
W.R. Czart, S. Robaszkiewicz
Abstract
I nst i tut e o f P hysi cs, A dam Mi cki ewi cz Uni versi ty Um ultowsk a 85, 61-61 4 Pozna¥ ( Recei ved Jul y 2, 2001)T w o-dim ension al ( d = 2 ) Penson À K olb mo del , i .e. t he ti ght-bindin g mo del with the pai r-hopp in g (intersite charge exchange ) interaction, is considered and the e˜ects of phase Ûuctuation s on the s -wave sup erconducti vi t y of this system are discussed w ithin the K osterlit z{T houl ess scenario.T he London penetration depth Ñ at T = 0 ; the K osterlitz-T houle ss critical temp erature T c , and the H artree{ Fock approximation critical temp erature T p are determined as a function of particle concentration and interaction.T he U emura typ e plots ( T c vs: Ñ À 2 ( 0) ) are derived.Beyond w eak coupli ng and for low concentrations they show the existence of universal scaling : T c ¿ 1=Ñ 2 ( 0) , as it w as previousl y found for the attractive H ubbard mo del and for the mo dels with intersite electron pairing.PAC S numb ers: 74.20.{z, 71.28.+ d, 74.25.H