Electronic and optical properties of cadmium fluoride: The role of many-body effects

Abstract

Electronic excitations and optical spectra of CdF2 are calculated up to ultraviolet employing state-of-the-art\ud techniques based on density functional theory and many-body perturbation theory. The GW scheme proposed\ud by Hedin has been used for the electronic self-energy to calculate single-particle excitation properties as energy\ud bands and densities of states. For optical propertiesmany-body effects, treated within the Bethe-Salpeter equation\ud framework, turn out to be crucial. A bound exciton located about 1 eV below the quasiparticle gap is predicted.\ud Within the present scheme the optical absorption spectra and other optical functions show an excellent agreement\ud with experimental data. Moreover, we tested different schemes to obtain the best agreement with experimental\ud data. Among the several schemes, we suggest a self-consistent quasiparticle energy scheme

Structure-property relationships in cubic cuprous iodide: A novel view on stability, chemical bonding, and electronic properties

“…To investigate how nonlocality contributes into the correction of the self-interaction error we investigated the electronic structure by means of the range-separated hybrid functional HSE06 [33][34][35][36]. Within hybrid functional formalism we adopted a strategy in which the amount of the exchange contribution is modeled by a material-dependent parameter -the inverse electronic dielectric constant [37][38].…”

Optical Properties

“…The HSE03/06 reference electronic structure and a self-consistent GW approximation are used. Adapted from results in [34] observation for Si, for rs-MgO [13] the QP effects shift the absorption spectrum toward the UV spectral region, here by about 3.0 eV. The position of the calculated and measured absorption edges approach each other.…”

“…The independent-quasiparticle approach, but adding local-field effects, is applied starting from the gKS problem based on the HSE03/06 hybrid functional. It is compared to the spectrum of the fully Coulomb-correlated electronhole pairs [34]. In the studied entire spectral region 0 < ω < 35 eV the two spectra are completely different indicating extremely strong excitonic effects in CdF 2 .…”

“…20.20 together with the imaginary part for a wide range of photon energies. BSE results [13,34] are compared with experimental data [46,47] for wurtzite-ZnO and fluorite-CdF 2 . In the case of wurtzite ordinary and extraordinary light polarizations are distinguished.…”

“…In the wz-ZnO case two spectra are shown related to ordinary/extraordinary light polarization or ordinary/extraordinary direction in the measurement geometry. From [13,34] from the absorption spectra in Figs …”