ELECTRONIC RAMAN-SCATTERING IN COPPER-OXIDE SUPERCONDUCTORS

Theoretical and experimental aspects of electronic Raman scattering in high-T-c superconductors are reviewed. Theoretical expressions for th e cross-section are derived and compared with data on various cuprate systems. The general goal is to obtain information about the symmetry of the superconducting order parameter. Experimental results are prese nted for Bi2Sr2CuO6, Bi2Sr2CaCu2O8 and Nd1.84Ce0.16CuO4. It is demonst rated that the class of hole-doped superconductors seems to be charact erized by a strong gap anisotropy reminiscent of unconventional d(x2-y 2) pairing. Electron-doped superconductors, on the other hand, show a behaviour which is more compatible with a conventional only slightly a nisotropic energy gap.