Correlated disorder as a way towards robust superconductivity

Ordinary superconductors are widely assumed insensitive to small concentrations of random nonmagnetic impurities, whereas strong disorder suppresses superconductivity and even makes superconductor-insulator transition occur. In between these limiting cases, a most fascinating regime can take place where disorder enhances superconductivity. Hitherto, almost all theoretical studies have been conducted under the assumption that disorder is completely independent and random. In real materials, however, positions of impurities and defects tend to correlate with each other. This work shows that these correlations have a strong impact on superconductivity making it more robust and less sensitive to the disorder potential. Superconducting properties can therefore be controlled not only by the overall density of impurities and defects, but by their spatial correlations as well.