Energy Scales in the Raman spectrum of electrons and hole doped cuprates within competing scenarios

Abstract

Recent experiments in underdoped hole-doped cuprates have shown the presence of two energy scales in the Raman spectrum in the superconducting state. This feature has a natural explanation in some models in which pseudogap and superconductivity compete. In electron-doped cuprates antiferromagnetic correlations are believed to survive in the superconducting state, and to produce a pseudogap above the critical temperature. Contrary to hole-doped systems, in electron-doped compounds only one energy scale appear since the pair breaking Raman intensity peaks in both B$_{1g}$ (antinodal) and B$_{2g}$ (nodal) channels at a frequency of a few meV, typical of the superconducting order parameter. In this paper we analyze the different effect in the Raman spectrum of the competition between pseudogap and superconductivity in electron and hole-doped cuprates. The difference in energy scales in both systems is explained in terms of the different truncation of the Fermi surface induced by the pseudogap. For electron-doped cuprates we also analyze the spectrum with antiferromagnetism and a non-monotonic superconducting order parameter.

7 pages, 4 postscript figures, minor changes in the text, Fig. 3 and Fig. 4 replaced to better visualize them