MOMENTUM DECOUPLING AND ANISOTROPIC S-WAVE OR D-WAVE HIGH-T-C SUPERCONDUCTIVITY

When the characteristic moments exchanged in the pairing scattering ar e small compared to the characteristic moments of the electronic DOS v ariations over the Brillouin zone, we have Momentum Decoupling implyin g different couplings in different regions of the Fermi surface. Aniso tropic s- and d-wave superconductivity are energetically degenerate an d both states are accessible depending on the magnitude and momentum s tructure of the Coulomb pseudopotential. Different high-T-c materials can have different gap symmetries and it is also possible to have tran sitions from s- to d-wave and vice versa by adjusting the doping. In t his scheme, high harmonics of the electronic DOS anisotropy do not con tribute to the damping while they contribute normally to the anisotrop ic pairing and this asymmetric damping-pairing contribution enhances s ignificantly T-c.