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 B-1g geometry can be explained by a strong fermionic self-energy due to the interaction with spin fluctuations. We compute the Raman intensity R(omega) both above and below T-c, and show that in both cases R(omega) 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 2 Delta peak in the superconducting state into a pseudo resonance mode below 2 Delta. We argue that these results agree well with the experimental data for Bi-2212. (C) 1999 Published by Elsevier Science Ltd. All rights reserved.