Fluctuation contribution to the specific heat in non-Fermi models for superconductivity

We investigated the fluctuation contribution to the specific heat of a two-dimensional superconductor with a non-Fermi normal state described by an Anderson-Green's function G(k, i omega) = omega (-alpha)(c)/(i omega - epsilon (k) )(1-alpha) The specific heat corrections contain a term proportional to (T-2 alpha - T-c(2 alpha))-'and another logarithmic one. We defined a coherence length as a function of the non-Fermi parameter a, which showed that a crossover study between BCS and Bose-Einstein condensation is possible by varying alpha in an interval 0-alpha (cr). By comparing our theoretical results with the experimental data for high critical temperature superconductor materials, we reobtained the value for a, corresponding to such systems, of the order 0.3-0.45. We also reobtained the critical temperature for such a superconductor using the Thouless criterion. (C) 2000 Elsevier Science B.V. All rights reserved.