Transport Properties of D -Wave Superconductors with Impurities

We extend our earlier analysis to the electronic thermal conductivity κ and the frequency-dependent electric conductivity σ(ω) at low temperatures where quasi-particle scattering is dominated by impurities. Both κ and σ 1 (0) at low temperatures increase with impurity concentration, implying that the pair breaking dominates the quasi-particle scattering. Further, σ 1 (ω) at T = 0 K is found to have a surprising non-Drudian sharp peak at ω = 0. The inclusion of this sharp structure appears to be indispensable for a proper analysis of the surface impedance data of Zn-doped high- T c cuprates.