Critical temperature of disordered d-wave superconductors with small coherence length

The critical temperature of d-wave superconductors with a small coherence length is studied numerically as a function of atomic disorder. Calculations are performed using the Bogolyubov-de Gennes method with inclusion of spatial nonuniformity of the superconducting order parameter. This approach allowed us to explain why the experimentally observed critical transition temperature decreases more slowly with increasing disorder than that predicted from the Abrikosov-Gor'kov theory. The quasilinear dependence of the critical temperature on the concentration of defects is also explained.