Superconducting fluctuations at arbitrary disorder strength
Abstract
We study the effect of superconducting fluctuations on the conductivity of metals at arbitrary temperatures T and impurity scattering rates τ^{1}. Using the standard diagrammatic technique but in the Keldysh representation, we derive the general expression for the fluctuation correction to the dc conductivity applicable for any space dimensionality and analyze it in the case of the film geometry. We observe that the usual classification in terms of the AslamazovLarkin, MakiThompson, and densityofstates diagrams is to some extent artificial since these contributions produce similar terms, which partially cancel each other. In the diffusive limit, our results fully coincide with recent calculations in the Keldysh technique. In the ballistic limit near the transition, we demonstrate the absence of a divergent term (T^{τ ) 2} attributed previously to the densityofstates contribution. In the ballistic limit far above the transition, the temperaturedependent part of the conductivity correction is shown to grow as T τ /ln(T /T_{c}) , where T_{c} is the critical temperature.
 Publication:

Physical Review B
 Pub Date:
 April 2018
 DOI:
 10.1103/PhysRevB.97.144517
 arXiv:
 arXiv:1711.07997
 Bibcode:
 2018PhRvB..97n4517S
 Keywords:

 Condensed Matter  Superconductivity;
 Condensed Matter  Disordered Systems and Neural Networks;
 Condensed Matter  Mesoscale and Nanoscale Physics
 EPrint:
 17 pages, 7 figures. A figure illustrating the temperature dependence of the fluctuation correction is added