Thermodynamics of Gaussian Fluctuations and Paraconductivity in Layered Superconductors
Abstract
A detailed theoretical analysis of the Gaussian fluctuations of the order parameter in layered superconductors is performed within the GinzburgLandau (GL) theory. The available results for the Gaussian fluctuations are systematized and a number of novel formulae for the fluctuation magnetization, nonlinear magnetic susceptibility, heat capacity and highfrequency conductivity in layered superconductors are derived. We propose several new prescriptions: how to determine the lifetime constant of fluctuation Cooper pairs τ_{0}, the inplane coherence length ξ_{ab}(0), the energy cutoff parameter <INLFIG><LINK LOCATOR="S0217979200001680IF001"></INLFIG> and the Ginzburg number ɛ_{Gi}. It is demonstrated, for example, how the spectroscopy of the lifetime can be used to verify the existence of depairing mechanisms in layered cuprates. The ultraviolet regularization of the GL free energy is carried out by means of the wellknown from the field theory ζfunction method. We further show that the archetype of the latter method has its origin in the century of enlightenment and the novel result is that the fluctuation part of the thermodynamic variables of the layered superconductors can be expressed in terms of the Euler Γfunction and its derivatives. Universal scaling curves for the magnetic field dependence of the paraconductivity σ_{ab}(T_{c},B), fluctuation magnetization M(T_{c},B) and the heat capacity C(T_{c},B) are found for the quasi2D superconductors at T_{c} and further related to the formfactor of the Cooper pairs.
 Publication:

International Journal of Modern Physics B
 Pub Date:
 2000
 DOI:
 10.1142/S0217979200001680
 arXiv:
 arXiv:condmat/0004023
 Bibcode:
 2000IJMPB..14.3831M
 Keywords:

 Condensed Matter  Superconductivity
 EPrint:
 48 pages, 2 figures, LaTeX. Final version: typos observed in the published paper corrected. See http://arXiv.org/abs/condmat/0004023v1 for first version of the manuscript: Mon, 3 Apr 2000 15:12:56 GMT