Computational Study of Optical Properties of Calcium Tungstate (CaWO4) Based on Density Functional Theory (DFT)

Abstract

This study theoretically investigated the optical properties of calcium tungstate (CaWO₄) in its scheelite phase using first-principles calculations based on Density Functional Theory (DFT), aiming to understand its interaction with electromagnetic radiation and assess its potential for optoelectronic and photonic applications. Conducted at the Department of Physics of the State University of Maranhão (UEMA), Brazil, between January and March 2025, the research employed the CASTEP module of the Materials Studio software to compute spectra for the complex refractive index, reflectivity, absorption coefficient, dielectric function, energy loss function, and optical conductivity, considering light polarization along the (1,0,0) direction and a 3×3×3 k-point mesh. The results revealed strong absorption in the extreme ultraviolet, with distinct features in the reflectivity, absorption, and conductivity spectra; the dielectric function exhibited dispersive behavior, and the energy loss function showed a pronounced peak in the violet region. Additionally, the simulated Raman spectra closely matched experimental data. These findings confirm that DFT-based methods offer a detailed characterization of CaWO₄’s optical response, supporting its potential use in optical and photonic devices.