Characterization of d and f Electronic States in RSn1.1Ge0.9 (R = Gd, Tb) Compounds by Optical Spectroscopy and Electronic‐Structure Calculations

This paper presents the results of investigations of the electronic structure and optical properties of the GdSn1.1Ge0.9 and TbSn1.1Ge0.9 compounds. Employing the local spin density approximation accounting for strong electronic correlations in the 4f‐shell of rare‐earth ions, that is the LSDA + U method, we carry out the spin‐polarized calculations of band structure. In a broad range of wavelengths the optical constants of the compounds are measured by an ellipsometry method. A number of spectral and electronic characteristics are calculated. Based on the calculated density of states the structural features of optical conductivity for the investigated intermetallic compounds are interpreted in the region of interband absorption. The electronic structure of ternary intermetallics GdSn1.1Ge0.9 and TbSn1.1Ge0.9 are studied by a combination of ab initio calculation of the band structure and measurement of optical properties. The spin‐polarized densities of electronic states are obtained by the LSDA+U method accounting for strong correlations in the 4f‐shell of the rare‐earth metals. Based on the calculations the structural features of optical conductivity for the compounds are interpreted in the region of interband absorption.