Effects of critical fluctuations and dimensionality on the jump in specific heat at the superconducting transition temperature: Application to YBa2Cu_3 O_7 - δ, Bi_2 Sr_2CaCu_2 O_8+δand KOs_2 O_6 compounds

Abstract

We report on a study of the superconducting order parameter thermodynamic fluctuations in ${\mathrm{YBa}}_2{\mathrm{Cu}}_3{\mathrm{O}}_{7-\delta }$, ${\mathrm{Bi}}_2{\mathrm{Sr}}_2{\mathrm{CaCu}}_2{\mathrm{O}}_{8+\delta }$ and ${\mathrm{KOs}}_2{\mathrm{O}}_6$ compounds. A non-perturbative technique within the framework of the renormalized Gaussian approach is proposed. The essential features are reported (analytically and numerically) through Ginzburg-Landau (GL) model-based calculations which take into account both the dimension and the microscopic parameters of the system. By presenting a self-consistent approach (SCA) improvement on the GL theory, a technique for obtaining corrections to the asymptotic critical behavior in terms of non universal parameters is developed. Therefore, corrections to the specific heat and the critical transition temperature for one-, two- and three-dimensional samples are found taking into account the fact that fluctuations occur at all length scales as the critical point of a system is approached. The GL model in the free-field approximation and the 3D-XY model are suitable for describing the weak and strong fluctuation regimes respectively. However, with a modified quadratic coefficient, the renormalized GL model is able to explain certain experimental observations including the specific heat of complicated systems, such as the cuprate superconductors and the $\beta$-pyrochlore oxides. It is clearly shown that the enhancement, suppression or rounding of the specific heat jump of high-$T_c$ cuprate superconductors at the transition are indicative of the order parameter thermodynamic fluctuations according to the dimension and the nature of interactions.

arXiv commentarXiv admin note: text overlap with arXiv:cond-mat/0109177 by other authors

References in corpus (8)

• Specific heat jump at the superconducting transition temperature in Ba(Fe(1-x)Cox)2As2 and Ba(Fe(1-x)Nix)2As2 single crystals
• New Pyrochlore Oxide Superconductor RbOs2O6
• Correlation Effects and Structural Dynamics in the $\beta$-Pyrochlore Superconductor KOs${}_2$O${}_6$
• 3D-XY critical fluctuations of the thermal expansivity in detwinned YBa2Cu3O7-d single crystals near optimal doping
• Specific Heat of the beta-Pyrochlore Oxide Superconductors CsOs2O6 and RbOs2O6
• Synthesis of superconducting pyrochlore RbOs2O6
• Effects of fluctuations and Coulomb interaction on the transition temperature of granular superconductors
• Nonadiabatic Fluctuations and the Charge-Density-Wave Transition in One-Dimensional Electron-Phonon Systems: a Dynamic Self-Consistent