Thermodynamic and electromagnetic properties of the Penson-Kolb model - art. no. 104511

We study thermodynamic and electromagnetic properties of the Penson-Kolb mo del, i.e., the tight-binding model with the pair-hopping interaction J, and analyze the effects of phase fluctuations on the s-wave superconductivity in this system. The evolution of the critical fields, the coherence length, the Ginzburg ratio, and the London penetration depth lambda with particles concentration it and pairing strength is determined at T=0 for d-dimension al hypercubic lattices d=2 (SQ) and d=3 (SC). Within the Kosterlitz-Thoules s scenario the critical temperatures T-c are calculated for d=2 SQ lattice and compared with the ones from BCS-HFA T-p. The results show a substantial enhancement of the gap to critical temperature ratio due to the phase fluc tuations as well as a separation of the energy scales for the pair formatio n (similar tok(B)T(p)) and the phase coherence (similar tok(B)T(c)). The Ue mura type plots, i.e., the T-c vs lambda (-2)(0) plots, are obtained both a s a function of n and as a function of pairing strength. The results are co mpared with those found earlier for the attractive Hubbard model.