RAMAN-SCATTERING INVESTIGATION OF THE SUPERCONDUCTING GAP ANISOTROPY IN LA2-XSRXCUO4

The low energy electronic Raman continua of a La1.83Sr0.17CuO4 single crystal have been obtained in several different scattering geometries, and for temperatures above and below Tc. Based upon the polarization dependence of the spectra obtained for T less than or equal to Tc it i s concluded that the superconducting gap is anisotropic with nodes loc ated near the (+/-1,+/-1) directions in reciprocal space and maxima cl ose to the kw and ky axes. The results are compared to spectra obtaine d from other high-Tc compounds and the possible compatibility df the r esults with particular gap functions is discussed.