Effect of Cu-doping on the electronic structure and optical properties of LaNi5

Optical properties of intermetallic isostructural compounds LaNi_5−xCu_x (x = 0, 0.6, 1, 1.2) have been studied in the spectral range from 0.22 to 15 μm using the ellipsometry method. It was found that the substitution of copper for nickel leads to local changes in the optical conductivity spectra. Theoretical calculations of the electronic structure and interband optical conductivity of LaNi_5−xCu_x compounds with x = 0, 1, 2, 3 were performed in the generalized gradient approximation within the pseudopotential plane-wave method PWSCF. Both the optical spectroscopic measurements and theoretical calculations demonstrate the presence of a broad absorption band around 4 eV associated with the Cu 3d → Ni 3d electron transitions and increasing with the growth of copper content.