Electronic Raman scattering in superconductors on triangle lattices

TL;DR

This paper investigates electronic Raman scattering in superconductors on triangle lattices, revealing polarization independence and highlighting impurity effects as tools to identify pairing symmetry, relevant to Na_xCoO_2·yH_2O superconductors.

Contribution

It demonstrates that Raman spectra in such superconductors are polarization-independent and emphasizes the importance of energy-shift and impurity effects for determining pairing symmetry.

Findings

Raman spectra are polarization-independent in triangle lattice superconductors.

Energy-shift dependence provides insights into pairing symmetry.

Impurity effects can help identify the pairing state.

Abstract

In superconductors on triangle lattices, we show that the electronic Raman spectra in the non-resonant channel are independent of the light polarization configuration in the scattering. Therefore the light polarization configuration is no longer a judicious choice to probe the anisotropic nature of the pairing wave function (as in the case of square lattices). However, we show that the detailed energy-shift dependence of the spectrum and the effects of impurities provide useful information that can help identify the possible pairing symmetry experimentally. These results are relevant to the newly discovered Na$_x$CoO$_2\cdot y$H$_2$O superconductors.