Infrared conductivity of a dx2-y2-wave superconductor with impurity and spin-fluctuation scattering.

Calculations are presented of the in-plane far-infrared conductivity of a dx2−y2-wave superconductor, incorporating elastic scattering due to impurities and inelastic scattering due to spin fluctuations. The impurity scattering is modeled by short-range potential scattering with arbitrary phase shift, while scattering due to spin fluctuations is calculated within a weak-coupling Hubbard model picture. The conductivity is characterized by a low-temperature residual Drude feature whose height and weight are controlled by impurity scattering, as well as a broad peak centered at 4∆0 arising from clean-limit inelastic processes. Results are in qualitative agreement with experiment despite missing spectral weight at high energies. 74.25.Nf, 74.72.-h, 72.10.Di, 72.10.Fk Typeset using REVTEX