RAMAN-STUDY OF THE ELECTRONIC CONTINUUM IN OXIDE SUPERCONDUCTORS

Systematic Raman-scattering experiments have been performed on YBa2Cu3O7 and Bi2Sr2CaCu2O8 single crystals between Tc and 270 K. At all four main symmetries the Raman-active electronic continuum is found to be almost constant up to energy transfers as high as 1 eV. Except for the (xy) symmetry in BSCCO, the low energy range of the spectra is dominated by a response function which is proportional to h{stroke}ω/kT. We suggest that different mechanisms of electronic relaxation, which are briefly discussed, may govern the Raman intensity. © 1990.