Electronic Raman scattering in superconductors on triangle lattices

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.