Universal behavior of the in-plane paraconductivity of cuprate superconductors in the short-wavelength fluctuation regime

Abstract

The in-plane paraconductivity was measured in the so-called high reduced-temperature region [for $\ensuremath{\varepsilon}\ensuremath{\equiv}\mathrm{ln}{(T/T}_{C})$ well above 0.1] in high-quality single crystals or epitaxial thin films of highly anisotropic cuprate superconductors with different number of superconducting layers per periodicity length. Although the high-$\ensuremath{\varepsilon}$ behavior of the paraconductivity cannot be described in terms of a critical exponent in \ensuremath{\varepsilon}, in all the cases we observe the same type of rapid fall-off at the same (well within the experimental uncertainties) reduced-temperature ${\ensuremath{\varepsilon}}^{C}\ensuremath{\simeq}0.7.$ These results may be explained in terms of the multilayered Gaussian-Ginzburg-Landau approach by taking into account that due to the uncertainty principle also above ${T}_{C}$ the superconducting coherence length cannot be appreciably smaller than at $T=0 \mathrm{K}.$