Electronic structure and optical properties of superconducting compounds ScGa3 and LuGa3.

The optical properties of bulk AuCu₃-type ordered superconducting binary compounds ScGa₃ and LuGa₃ have been experimentally investigated for the first time in the wide spectral range and explained in terms of the band structure. First-principles calculations of electronic densities of states and optical conductivities are performed within the framework of LSDA+U method using the LMTO-ASA software package. The measured dielectric functions spectra for both materials exhibit a strong absorption region above ∼ 1 eV, which are in a reasonable agreement with the calculated metal-like energy structures of compounds. Features of quantum light absorption are discussed on the basis of a comparative analysis of experimental and theoretical spectra of interband optical conductivity. Plasma and relaxation frequencies of conduction electrons are determined. [ABSTRACT FROM AUTHOR]