Raman properties intrinsic to superconductivity in the Bi-Sr-Ca-Cu-O system

Previous Raman studies of the Bi-Sr-Ca-Cu-O system have provided an abundance of interesting results including the existence of an electronic continuum which redistributes below Tc, an anomalous phonon renormalization effect, and Fano antiresonance behavior of the 290-cm-1 vibrational mode. We attempt in this paper to determine what connection these features may have to the superconducting behavior of this compound. In order to draw such conclusions a systematic study has been carried out on numerous Bi2Sr2CaCu2O8+Δ samples. Our Raman investigations indicate that it is the continuum redistribution and a linear low-energy contribution to the scattering intensity at temperatures T much-lt Tc that are intrinsic to superconductivity in this system