Quasiparticle scattering time in P-wave-superconductors

Abstract

The authors show that the quasiparticle scattering time, due to nonmagnetic impurities diverges at zero energy in anisotropic superconductors with zeroes in the order parameter at points and on lines on the Fermi surface. They assume S-wave scattering from the impurities and carry out the calculations in the weak coupling limit. As a result of the energy dependence of the scattering time, the quasiparticle mean free path diverges at zero energy. This is in contrast to the BCS result where the mean free path is equal to its constant normal state value. The consequences of this for the ultrasonic attenuation are discussed.