Impurity effects ind-wave superconductors

Impurity scattering will provide a crucial test for d-wave superconductor in high ${\mathit{T}}_{\mathit{c}}$ copper-oxides. Among other things we calculate the static spin susceptibility and find a simple relation between the susceptibility and superfluid density ${\mathrm{\rho }}_{\mathit{s}}$(T)=[λ(0)/λ(T)${]}^2$ is broken in the presence of impurity scattering. Also we generalize Lee’s universal conductivity at T=0 K. In the presence of a finite concentration of impurity, the order parameter ${\mathrm{\Delta }}_{00}$ in the conductivity has to be replaced by Δ(Γ,0) and Δ(Γ,0) is accessible through the tunneling experiment of the density of states.