Energy scales in the Raman spectrum of electron- 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 are believed to produce a pseudogap above the critical temperature. Contrary to hole-doped systems, in electron-doped compounds only one energy scale appears 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 effects 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 nonmonotonic superconducting order parameter.