We study the effect of a nonmagnetic impurity on the relaxation of the charge imbalance in a d-wave superconductor. We compute the electric field as a function of distance in the normal-metal–superconductor junction, while taking into account the effect of the impurity scattering, gap anisotropy, Andreev scattering, and crystal orientation of the order parameter. We compare the results with a highly anisotropic s-wave superconductor and also discuss the effect of the electron-phonon scattering. © 1996 The American Physical Society.

• Received 21 February 1996

DOI:https://doi.org/10.1103/PhysRevB.54.3044