Ab initio modeling of electronic and optical properties of hafnium silicates

Ab initio calculations are used to investigate the electronic structure and optical properties of crystalline monoclinic hafnium silicates (Hf1−xSixO2) as a function of silicon content x (x = 0, 0.25, 0.50, and 0.75). Densities of states (DOS), electronic band gaps, refractive indices and extinction coefficients of Hf1−xSixO2 are calculated through a screened exchange (sX) method within the local density approximation (LDA). Calculational results of the DOS of Hf1−xSixO2 indicate that these oxides are insulators. Electronic band gaps of Hf1−xSixO2 are found to increase with increasing the silicon content. The results of optical constants of Hf1−xSixO2 show that increasing silicon content produces a lower refractive index and a smaller extinction coefficient. The present predicted results exhibited a good agreement with the recently reported experimental observations.