Optical and dielectric characteristics of semimetallic compounds Y$_x$La$_{1-x}$Bi (0 $\le x\le$ 1)

The results of experimental studies of the optical and dielectric properties of cubic compounds Y$_x$La$_{1-x}$Bi are presented. In the spectral range 0.22–15 $\mu$m, the refractive indices and absorption coefficients were measured ellipsometrically, using which the energy dependences of the dielectric constant, reflectivity, optical conductivity and the function of characteristic electron losses were calculated. The features of quantum light absorption are interpreted on the basis of a comparative analysis of experimental and theoretical optical conductivity spectra. The anomalous behavior of spectral characteristics in the infrared range of the spectrum confirms the semi-metallic nature of the compounds.