Electronic Raman scattering in superconducting cuprates

We show that the novel features observed in Raman experiments on optimally doped and underdoped Bi-2212 compounds in B1g geometry can be explained by a strong fermionic self-energy due to the interaction with spin fluctuations. We compute the Raman intensity ROvU both above and below Tc, and show that in both cases ROvU 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 2D peak in the superconducting state into a pseudo resonance mode below 2D. We argue that these results agree well with the experimental data for Bi-2212. q 1999 Published by Elsevier Science Ltd. All rights reserved.