REFLECTANCE AND RAMAN-SPECTRA OF METALLIC OXIDES, LASRCOO AND CASRRUO- RESEMBLANCE TO SUPERCONDUCTING CUPRATES

We have measured reflectance, ellipsometric, and Raman spectra on thin films of isotropic metallic oxides La0.5Sr0.5CoO3 and Ca(0.5)Sr(0.5)R uO3. The spectra strongly resemble those of cuprate superconductors. I n particular, reflectance is a nearly linear function of frequency thr oughout the infrared, and the electronic Raman scattering continuum is nearly independent of energy. Neither of the compounds is superconduc ting down to 4.2 K, while their electronic excitations spectra are app arently like those of the cuprates. Hence, it seems unlikely that the corresponding ''anomalous'' dielectric response could be the sole root of high-temperature superconductivity.