We show that the novel features observed in Raman experiments on optimally
doped and underdoped Bi-2212 compounds in B1gβ geometry can be explained by
a strong fermionic self-energy due to the interaction with spin fluctuations.
We compute the Raman intensity R(Ο) both above and below Tcβ, and show
that in both cases R(Ο) progressively deviates, with decreasing doping,
from that in a Fermi-gas due to increasing contribution from the fermionic
self-energy. We also show that the final state interaction increases with
decreasing doping and gradually transforms the 2Ξ peak in the
superconducting state into a pseudo resonance mode below 2Ξ. We argue
that these results agree well with the experimental data for Bi-2212.Comment: 6 pages, 4 eps figures. To appear in Solid State Com