Anisotropic order parameters with s-and d-wave-like symmetry and the transition temperature in high-T_c layered superconductors

Abstract

The wave-vector dependence of superconducting order parameters and the corresponding transition temperature in three-dimensional layered metals are investigated. It includes planar anisotropic s-wave-like as well as d-wave-like pairing contributions, but for simplicity only intralayer pairing of electrons has been considered for tetragonal and orthorhombic crystal structures, relevant to high-T_c materials. It is shown that for the orthorhombic case order parameters are likely to have mixed symmetry, whereas in tetragonal structures it is possible to have only planar d-wave-like symmetry with a possible correction term with an additional wave-vector dependence in the direction perpendicular to the reciprocal layer plane.