DISORDER EFFECTS IN THE T-J MODEL

We investigate the effects of disorder in the single-band t-J model, mainly devoting our analysis to the superconducting phases with d-wave or s-wave symmetry. We present evidence that, in the presence of strong correlation with reduced bandwidth and Van Hove singularity in the density of states, a self-consistent approach for the self-energy associated to the impurities is required. Numerical estimates of the reduction of the critical temperature with disorder are given. When a constant imaginary part of the self-energy is taken, avoiding self-consistency, the reduction of the critical temperature is overestimated. © 1995 The American Physical Society.