ELECTRON-ENERGY-LOSS SPECTRUM OF THE CUPRATE SUPERCONDUCTORS

We present a theoretical description of the near-specular (dipole) ele ctron-energy-loss spectrum of a superlattice constructed from anisotro pic dielectric layers, as a model of the superconducting copper-oxide- based materials. The theory is applied to a description of recent data taken on the Bi 2:2:1:2 compound. We find that parameters deduced fro m the electron loss spectrum are compatible with infrared reflectivity data. Manifestations of the superconducting energy gap are not eviden t in the new data.