Temperature dependence of electronic Raman scattering as a probe of pairing symmetry in high-Tc superconductors

The temperature dependence of electronic Raman scattering has been studied in Bi2Sr2CaCu2O8+δ crystals. In optimally doped crystals, the temperature dependence of static Raman (ω→0) slope suggests that the gap nodes are shifted from the positions prescribed by a pure d-wave pairing. The low-frequency part of B1g spectra as a function of disorder gives further evidence of a mixed order parameter.