Uniform impurity scattering in two-band $s_{\pm }$ and $s_{++}$ superconductors

Abstract

The $s_{\pm }$ and $s_{++}$ models for the superconducting state are subject of intense studies regarding Fe-based superconductors. Depending on the parameters, disorder may leave intact or suppress $T_c$ in these models. Here we study the special case of disorder with equal values of intra- and interband impurity potentials in the two-band $s_{\pm }$ and $s_{++}$ models. We show that this case can be considered as an isolated point and $T_c$ there has maximal damping for a wide range of parameters.

5 pages, submitted to J. Supercond. Nov. Magn., talk on this subject was presented at the 5th International Conference "Fundamental Problems of High-Temperature Superconductivity" (FPS'15) http://fps15.lebedev.ru/en/