VANHOVE SINGULARITIES AND HIGH-TC SUPERCONDUCTIVITY - A REVIEW

This review describes a Fermi liquid picture of high-T(c) superconductivity. A density-of-states (dos) peak associated with the CuO2-plane van Hove singularity causes a peak in T(c) as a function of hole doping. Strong correlation effects drive a Mott transition at half filling. For intermediate doping, the electronic system is unstable against phase separation, with one phase near the insulating state, the other near the T(c) peak. The large dos leads to competition between superconductivity and structural instability, in analogy with the A15 compounds. The superconductivity appears to be driven by strong electron-phonon coupling, enhanced by fluctuation effects.