Theoretical and Experimental Studies on the Crystal Structure, Electronic Structure and Optical Properties of SmTaO4

The crystal structure, electronic structure and optical properties of SmTaO4 were identified through an experimental method and first principles calculation. X-ray powder diffraction (XRD) and a spectrophotometer were used to characterize the crystal structure, reflectivity and band gap of this material; furthermore, the electronic structure and optical properties were investigated according to three exchange-correlation potentials, LDA, GGA and GGA + U. Results show that the SmTaO4 calcined at 1400 degrees C with the solid-state reaction method is in monoclinic phase in the space group I-2/a. In addition, the calculated lattice parameters are consistent with the experimental values. The electron transitions among the O 2p states, Sm 4f states and Ta 5d states play a key role in the dielectric function, refractive index, absorption coefficient and reflectivity of SmTaO4. The calculation of first principles provides considerable insight into the relationship between the electronic structure and optical properties of this material.