Effect of disorder on the pairing properties of electron-doped high-Tcsuperconductors

Abstract

The effect of disorder on pairing properties in the mixed d x 2 −y 2 + is-and d x 2 −y 2 + id xy -wave pairing states in electron-doped high-T c cuprates is investigated by self-consistently solving the Bogoliubov-de Gennes equations. It is found that the dominant d x 2 −y 2-wave component will give way to the s-wave component, while the d xy -wave component will have the same magnitude as the d x 2 −y 2-wave component with the increase of disorder strength. In real space, the d xy -wave component competes locally with the d x 2 −y 2-wave component, while the s-wave component does not seem to show such competition with the latter. Both transitions from the d x 2 −y 2-wave pairing to the mixed d x 2 −y 2 + is-wave pairing and to the mixed d x 2 −y 2 + id xy -wave pairing can result in the absence of zero-bias peaks in the local tunneling spectra, but it has a U-shaped form for the former and a V-shaped form for the latter. These results may serve to probe the pairing symmetry in the electron-doped cuprates.