VANHOVE EXCITONS AND HIGH-TC SUPERCONDUCTIVITY .5. ELECTRON-PHONON INTERACTION

A model is developed for electron-phonon interaction in the new superconducting oxides, showing that the system is nearly unstable with respect to a charge density wave, but that weak interlayer coupling generally prevents the establishment of true long-range order. It is shown that the associated mode softening produces a significant Tc enhancement, but probably not large enough to fully account for the experimental results. Suggestions are made for an additional coupling mechanism, probably associated with fluctuations into the ordered phase. © 1990.