Relative permittivity of alumina obtained from density functional theory with band gap corrections from hybrid functionals
Abstract
The generalized gradient approximation within density functional theory is commonly used to predict the structural properties of materials from first principles. However, it significantly underestimates band gaps, leading to inaccurate predictions for the optical properties of insulators. In this work, we use a hybrid functional to obtain a better estimate for the band gap and apply a correction method to calculate the relative permittivity of α-alumina. Our results provide good estimates for the indices of refraction of this material that are within 2% of experimental values.
