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 R(ω) both above and below Tc, and show that in both cases R(ω) 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 2Δ peak in the superconducting state into a pseudo resonance mode below 2Δ. We argue that these results agree well with the experimental data for Bi-2212.
Bibliographical noteFunding Information:
It is our pleasure to thank T. Devereaux, R. Gatt, R. Joynt, M. V. Klein, A. Millis, H. Monien, D. Pines and J. Schmalian for useful conversations. The research was supported by NSF grant DMR-9629839 (A.C.) and by the NSF cooperative agreement DMR91-20000 through STCS (D.M. and G.B.).
Copyright 2017 Elsevier B.V., All rights reserved.