Theoretical and experimental studies of Ba₂SmTaO₆ on crystal structure, electronic structure and optical properties

The crystal structure, electronic structure and optical properties of Ba₂SmTaO₆ have been studied by first-principles calculation, including GGA and GGA+U, as well as by experimental methods. The calculated lattice parameters are in good agreement with the previously reported values. First-principles calculation provides considerable insight into the relationship between electronic structure and optical properties. The electronic transitions among O 2p states, Sm 4f states and Ta 5d states play a key role in optical properties, including dielectric function, refractive index, absorption coefficient and reflectance. The results confirmed that both tetragonal and cubic phases of Ba₂SmTaO₆ have a particularly high reflectance (up to 97% at 1.06 μm). This high reflectance, which is comparable to metallic materials, makes Ba₂SmTaO₆ a good candidate for potential applications in the anti-infrared radiation area.