Superconducing Alloys with Weak and Strong Scattering: Anderson's Theorem and a Superconductor-Insulator Transition

Abstract

We have studied the effects of strong impurity scattering on disordered superconductors beyond the low impurity concentration limit. By applying the full CPA to a superconductiong A-B binary alloy, we calculated the fluctuations of the local order parameters ${\Delta }_A,{\Delta }_B$ and charge densities, $n_A,n_B$ for weak and strong on site disorder. We find that for narrow band alloy s-wav e superconductors the conditions for Anderson's theorem are satisfied in general only for the case of particle-hole symmetry. In this case it is satisfied regardless whether we are in the weak or strong scattering regimes. Interestingly, we find that strong scattering leads to band splitting and in this regime for any band filling we have a critical concentration where a superconductor-insulator quantum phase transition occurs at T=0.

28 pages, 13 figures

References in corpus (5)

• Role of Spatial Amplitude Fluctuations in Highly Disordered s-Wave Superconductors
• Quantum Monte Carlo Study of the Disordered Attractive Hubbard Model
• Coherent Potential Approximation for `d - wave' Superconductivity in Disordered Systems
• Effect of spatial variations of superconducting gap on suppression of the transition temperature by impurities
• Van Hove Singularity and D-Wave Pairing in Disordered Superconductors

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• Full orbital decomposition of Yu-Shiba-Rusinov states based on first principles
• Validity of Anderson's theorem for s-wave superconductors
• 'Pi State' Induced by Impurities with a Repulsive Interaction
• Variations of Pairing Potential and Charge Distribution in Presence of a Non-magnetic Impurity
• Specific Heat of Disordered Superconductors Induced by Negative Centers
• Superfluid weight in disordered flat-band superconductors as a competition between localization functionals