Polarization dependence of the electronic Raman spectra of Ca-substituted YBCO single crystals: As a probe of s-wave mixing in the superconducting gap

We measured Raman spectra of a series of Ca-substituted and oxygen- controlled YBCO single crystals at low temperatures. It was found that the change of pair-breaking peak energy and intensity of A1g and B1g were explained with carrier concentration rather than orthorhombic lattice distortion.