Resonating valence bonds andd-wave superconductivity

We show that the resonating-valence-bond mechanism for high-Tc superconductivity can lead to s-wave- and d-wave-like superconducting order parameters. The critical temperature for d-wave ordering is higher close to half-filling. At low temperatures, a mixture of d and s waves with a well-defined phase opens a full gap in the quasiparticle spectrum.