Raman superconducting state response

Note, from eq. (30), that in an s-wave superconductor, the unscreened superconducting-state Raman scattering response, oclm yy, is zero for 0)<2A, but has a scattering... 

While the calculations of Devereaux et al. and others appear to show that many of the anomalous features observed in the superconducting-state electronic Raman scattering response of high-Fc cuprates can be explained assuming a d 2 pairing state, there are several noteworthy exceptions to this interpretation. 

Fig. 18. Symmetry dependence of electronic Raman scattering in the superconducting state of overdoped Tl2Ba2CuO i (after Gasparov et al. 1998a,b), showing the or low-frequency dependence of the Bj scattering response and the linear-in-m dependence in A g and Big.

Raman spectra indicate that phonons are coupled to electronic states in BaPb BijPj (53) and in Ba1.xKxBiOs (58). These studies do show a strong electron - phonon interaction is present in the superconducting phases, but do not prove that these modes are responsible for high Tc driven by a phonon - only mechanism. 

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