PLASMON MODES IN A SYSTEM COMPOSED OF CU-O LAYERS AND CHAINS

Abstract

Based on a free-electron model of both the quasi-two-dimensional CuO2 layers and the quasi-one-dimensional Cu-O chains in high-T(c) Y-Ba-Cu-O superconductors, we have calculated in this simplified system various Coulombic electron-electron interacting potentials V(q), dielectric functions, dispersion relations, and various plasmon modes, including in particular the acoustic plasmons. The main contribution of the chains is to stabilize, isolate, and generate more acoustic plasmons-omega- which provide a pairing mechanism for high-T(c) superconductivity.