Electronic Raman scattering in YBa2Cu3O7 and other superconducting cuprates

Superconductivity-induced structures in the electronic Raman spectra of high-T-c superconductors are computed using the results of ab initio local-density approximation linear muffin-tin-orbital three-dimensional band-structure calculations via numerical integrations of the mass fluctuations, either in the whole three-dimensional Brillouin zone or limiting the integrations to the Fermi surface. The results of both calculations are rather similar, the Brillouin-zone integration yielding additional weak structures related to the extended van Hove singularities. Similar calculations have been performed for the normal state of these high-T-c cuprates. Polarization configurations have been investigated and the results have been compared to experimental spectra. The assumption of a simple d(x2-y2)-like gap function allows us to explain a number of experimental features but is hard to reconcile with the relative positions of the A(1g) and B-1g peaks.