INTERPRETATION OF THE PLASMON DISPERSION IN THE ELECTRON-ENERGY-LOSS SPECTRA OF HIGH-TC SUPERCONDUCTORS

Electron-loss spectroscopy has recently been used to investigate monoc rystals of multilayered high-T(c) superconductors, like Bi2Sr2CaCu2O8. The position of the plasmon peak has been measured as a function of t he magnitude and orientation of the momentum transfer parallel to the CuO2 layer planes. In this paper it is shown that these spectra can be consistently interpreted if one uses a model taking into account the multilayered structure of the crystal as well as the square shape of t he Fermi curve (for half-filled Brillouin zone). Moreover direct infor mation can be obtained regarding the background dielectric constant, t he effective mass of the charge carriers, and the Fermi energy.