Pseudogap and superconductivity in the t-J model

In the framework of the planar t-J model for cuprates we analyze the development of a pseudogap in the density of states. For finite doping with short range anti ferromagnetic (AFM) order the spectral function retains large incoherent contribution in the hole part and exhibits large Fermi surface. At low-doping we observe the effective truncation of the large Fermi surface and the evolution of hole-pocket-like Fermi surface, reduced electron density of states and at the same time quasiparticle (QP) density of states at the Fermi level. The Green's functions obtained with this method in the regime of optimum doping are taken as an input and the Eliashberg equations are further solved in the weak coupling limit. Resulting gap function with d-wave symmetry and the critical temperature are in the regime relevant to cuprates. (C) 2004 Elsevier B.V. All rights reserved.