7 J un 1 99 9 p - wave and d - wave superconductivity in quasi - 2 D metals

We compare predictions of the mean-field theory of superconductivity for nearly antiferromagnetic and nearly ferromagnetic metals in two dimensions. The calculations are based on a parametrization of the effective interaction arising from the exchange of magnetic fluctuations. The Eliashberg equations for the transition temperature are solved including the full momentum dependence of the electron self-energy. The results show that for comparable parameters d-wave singlet pairing in nearly antiferromagnetic metals is generally much stronger than p-wave triplet pairing in nearly ferromagnetic metals in quasi two dimensions. The relevance to the layered materials, and in particular Sr 2 RuO 4 that exhibits p-wave triplet pairing, is discussed.