Gap inhomogeneities and the density of states in disordered d-wave superconductors
We report on a numerical study of disorder effects in 2D d-wave BCS superconductors. We compare exact numerical solutions of the Bogoliubov-de Gennes (BdG) equations for the density of states rho(E) with the standard T-matrix approximation. Local suppression of the order parameter near impurity sites, which occurs in self-consistent solutions of the BdG equations, leads to apparent power-law behavior rho(E) approximately |E|(alpha) with nonuniversal alpha over an energy scale comparable to the single-impurity resonance energy Omega(0). We show that the novel effects arise from static spatial correlations between the order parameter and the impurity distribution.
Atkinson
WA
Department of Physics, University of Florida, P.O. Box 118440, Gainesville, Florida 32611, USA.
Hirschfeld
PJ
MacDonald
AH