EFFECTIVE-MEDIUM, MODELS FOR CUPRATE HIGH-TEMPERATURE SUPERCONDUCTIVITY ARE INCOMPLETE AND MISLEADING

To demonstrate the first part of the titled statement we discuss examples of large effects at or very near T-c associated with lattice instabilities. We then verify, again with examples, how such models are indeed misleading. The examples discussed include structural changes near T-c as measured by neutron diffraction and ion channeling, capacitance changes as measured for a superconductive electrode/electroyte double layer, phonon softening measured by Raman scattering and neutron diffraction, thermal difference reflectance spectra, persistent photoconductivity, isotope shifts, pressure-induced oxygen ordering effects, NMR studies of paramagnetic center densities, reflectance and Raman studies of sub-gap continua,. photoemission studies of states near E(F), linearly temperature-dependent normal-state transport properties, broadening of the resistive transition by a magnetic field, and finally we address the question of why T-c is so high in some cuprates.