Raman continuum in high-$T_c$ superconductors

TL;DR

This paper investigates the Raman continuum in high-$T_c$ superconductors, explaining observed peak separation and doping dependence through calculations based on the modified spin bag model.

Contribution

It provides a theoretical explanation for the anomalous peak separation and doping dependence observed in Raman spectra of high-$T_c$ superconductors.

Findings

Calculated Raman intensities match experimental peak separation

Peak positions are insensitive to doping in one geometry

Doping shifts the other peak towards higher frequencies

Abstract

Experimentally, Raman continuum for $A_g$ and $B_g$ geometry exhibits peaks far apart from each other (about 80 to 150 $\rm cm^{-1}$) in frequency. The former is insensitive to doping over a small range where $T_c$ does not vary much whereas the latter shifts towards higher frequencies. We calculate the electronic Raman scattering intensities using the `modified spin bag model'. We show that the calculated results have natural explanation to the observed anamolous peak separation and peculiar doping dependence.