Effects of (non-)magnetic disorder in quasi-1D singlet superconductors

We study the competition between disorder and singlet superconductivity in a quasi-1d system. We investigate the applicability of the the Anderson theorem, namely that time-reversal conserving (non-magnetic) disorder does not impact the critical temperature, by opposition to time-reversal breaking disorder (magnetic). To do so we examine a quasi-1d system with forward scattering disorder.

We find that for non-magnetic disorder the Anderson theorem also holds in the quasi-1D geometry. On the contrary, magnetic disorder has an impact on the critical temperature, that we investigate by deriving renormalization group equations describing the competition between the disorder and the interactions. Computing the critical temperature as a function of disorder strength, we see that different regimes arise depending on the strength of interactions.