Superconductivity in the exactly solvable model of pseudogap state: The absence of self-averaging
É. Z. Kuchinskii, M. V. Sadovskii
The features of the superconducting state are studied in the simple exactly solvable model of the pseudogap state induced by fluctuations of the short-range “dielectric” order in the model of the Fermi surface with “hot” spots. The analysis is carried out for arbitrary short-range correlation lengths ξ corr . It is shown that the superconducting gap averaged over such fluctuations differs from zero in a wide temperature range above the temperature T c of the uniform superconducting transition in the entire sample, which is a consequence of non-self-averaging of the superconducting order parameter over the random fluctuation field. In the temperature range T > T c , superconductivity apparently exists in individual regions (drops). These effects become weaker with decreasing correlation length ξ corr ; in particular, the range of existence for drops becomes narrower and vanishes as ξ corr → 0, but for finite values of ξ corr , complete self-averaging does not take place.
arXiv:cond-mat/0110013•Journal of Experimental and Theoretical Physics•Mar 1, 2002•3 citations