Effects of disorder on lattice Ginzburg-Landau model of d-wave superconductors and superfluids
Abstract
We study the effects of quenched disorder on the two-dimensional d-wave superconductors (SC's) at zero temperature by Monte-Carlo simulations. The model is defined on the three-dimesional (3D) lattice and the SC pair field is put on each spatial link as motivated in the resonating-valence-bond theory of the high-T c SC's. For the nonrandom case, the model exhibits a second-order phase transition to a SC state as density of charge carriers is increased. It belongs to the universality class different from that of the 3D XY model. Quenched disorders (impurities) are introduced both in the hopping amplitude and the plaquette term of pair fields. Then the second-order transition disappears at a critical concentration of quenched disorder, pc 15%. Implication of the results to cold atomic systems in optical lattices is also discussed.