The effect of disorder on electronic structure and conducting properties of superconductors with various kinds of pairing symmetries

A detailed review of the effect of disorder on superconductivity is done for single band and multiband systems with attractive pairing interactions. We shall go on to investigate the situation where interband interaction is repulsive and intraband interaction is attractive. Such pairing represents a “± s-wave superconductor”. We find that if the form of the intraband pairing potential is nonlocal then superconductivity survives even when the repulsive interband interaction is dominant. Randomness in interband pairing potential is able to kill superconductivity in such a system.