SELF-CONSISTENT CALCULATIONS OF SUPERCONDUCTIVITY IN A NEARLY ANTIFERROMAGNETIC FERMI-LIQUID

Within a Hubbard model with on-site repulsion U and nearest-neighbor hopping tBAR in the two-dimensional copper oxide plane, we have carried out self-consistent calculations of the superconducting critical temperature T(c) resulting from spin and charge fluctuations. The gap is found to have d(x2-y2) symmetry and T(c) congruent-to 0.016tBAR. Superconductivity exists only for a narrow range of U, very near the antiferromagnetic instability (U(c)). In this region near U(c), the Stoner enhancement in the incommensurate peaks of the spin susceptibility near (pi,pi) is of order 100-200. The absolute size of the peaks at T(c) is of the same order as measured, as is also the relative height of peaks to background. However, the theory predicts a suppression of these structures as T is reduced below T(c) which is much faster than observed.