SELF-CONSISTENT CALCULATIONS OF ELIASHBERG EQUATION FOR STRONG-COUPLING SUPERCONDUCTIVITY WITH ANISOTROPIC GAP UNDER THE MODULATION OF 2 KINDS OF NODAL WAVE-VECTORS TO 2-DIMENSIONAL ELECTRONIC BANDS

We investigate the role of the competition between two kinds of waveve ctors Q in the appearance of an anisotropic superconducting gap in 2-d imensional systems on a square lattice with strong antiferromagnetic c orrelations. We take into account the effect of interaction between ca rriers via wavevectors, Q(1) = (+/-pi/a, +/-pi/a) and Q(2x) = (+/-pi/a , 0), Q(2y) = (0, +/-pi/a). (Here, a is the lattice constant.) We trea t the strong coupling superconductivity by using Eliashberg-Migdal equ ations for superconducting phases. On the basis of the numerical calcu lation, we discuss how the symmetric properties of the gap and values of T-c are related to the ratio of the strength of interactions for Q( 1) and Q(2).