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Regular version of the site

Article

Paraconductivity of pseudogapped superconductors

Physical Review B: Condensed Matter and Materials Physics. 2018. Vol. 97. P. 014506-1-014506-14.
Poboiko I., Feigelman M.

We calculate Aslamazov-Larkin (AL) paraconductity σAL(T) for a model of strongly disordered superconductors (dimensions d=2,3) with a large pseudogap whose magnitude strongly exceeds transition temperature Tc. We show that, within Gaussian approximation over Cooper-pair fluctuations, paraconductivity is just twice larger that the classical AL result at the same ε=(T−Tc)/Tc. Upon decreasing ε, Gaussian approximation is violated due to local fluctuations of pairing fields that become relevant at ε≤ε1≪1. Characteristic scale ε1 is much larger than the width ε2 of the thermodynamical critical region, that is determined via the Ginzburg criterion, ε2≈εd1. We argue that in the intermediate region ε2≤ε≤ε1, paraconductivity follows the same AL power law, albeit with another (yet unknown) numerical prefactor. At further decrease of the temperature, all kinds of fluctuational corrections become strong at ε≤ε2; in particular, conductivity occurs to be strongly inhomogeneous in real space.