We investigate the complex conductivity of a highly disordered MoC superconducting film with kFl≈1, where kF is the Fermi wavenumber and l is the mean free path, derived from experimental transmission characteristics of coplanar waveguide resonators in a wide temperature range below the superconducting transition temperature Tc. We find that the original Mattis-Bardeen model with a finite quasiparticle lifetime, τ, offers a perfect description of the experimentally observed complex conductivity. We show that τ is appreciably reduced by scattering effects. Characteristics of the scattering centers are independently found by the scanning tunneling spectroscopy and agree with those determined from the complex conductivity.
@article{arxiv.1407.2402,
title = {Finite quasiparticle lifetime in disordered superconductors},
author = {M. Žemlička and P. Neilinger and M. Trgala and D. Manca and M. Grajcar and P. Szabo and P. Samuely and Š. Gaži and U. Hübner and V. M. Vinokur and E. Il'ichev},
journal= {arXiv preprint arXiv:1407.2402},
year = {2015}
}