Thermodynamic properties of D-wave paired superconductors

The D-wave paired Fermi system is considered in the frame of generalized gap equation obtained in BCS-like approach. It is shown that the thermodynamic functions of a system, as the thermodynamic potential, entropy, and heat capacity differences between the normal and superconducting state are precisely defined functionals of the energy gap as a function of temperature. The derived formulas are identical as those obtained for s-wave paired Fermi system. It states that the developed formalism can be applied, in practice, to investigation of real superconductors in which a singlet state is realized. Some numerical results illustrating prospects and capabilities of the presented formalism are given for chosen structures of the order parameter. (author)