Electronic and optical properties of Cadmium fluoride: the role of many-body effects

TL;DR

This study uses advanced many-body computational techniques to accurately predict the electronic and optical properties of cadmium fluoride, highlighting the importance of many-body effects and excitons in optical spectra.

Contribution

It demonstrates the application of GW and Bethe-Salpeter methods to cadmium fluoride, providing detailed insights into excitonic effects and improving agreement with experimental data.

Findings

Identification of a bound exciton about 1 eV below the quasiparticle gap

Excellent agreement between calculated and experimental optical spectra

Self-consistent quasiparticle energy scheme yields best results

Abstract

Electronic excitations and optical spectra of $CdF_{2}$ are calculated up to ultraviolet employing state-of-the-art techniques based on density functional theory and many-body perturbation theory. The GW scheme proposed by Hedin has been used for the electronic self-energy to calculate single-particle excitation properties as energy bands and densities of states. For optical properties many-body effects, treated within the Bethe-Salpeter equation framework, turn out to be crucial. A bound exciton located about 1 eV below the quasiparticle gap is predicted. Within the present scheme the optical absorption spectra and other optical functions show an excellent agreement with experimental data. Moreover, we tested different schemes to obtain the best agreement with experimental data. Among the several schemes, we suggest a self-consistent quasiparticle energy scheme.