Calculation of the electronic and optical properties of LiFe5O8: An ab initio study

Abstract

Ab initio calculations based on density functional theory have been employed to study electronic and optical properties of lithium ferrite spinel (LiFe5O8, LFO) based on density functional theory. The calculated of structural properties are in a good agreement with previously reported experimental results. The calculated band gap is indirect with a value of 2.3 eV, which overestimated the experimental value of 1.9 eV. The top of the valence band and the bottom of the conduction band of the LFO are dominated by the 3d states of Fe3+(1) (8c site) and Fe3+(2) (12d site). The magnetic moment calculated for the ion of Fe3+ 12d site was 3.90 μβ and 3.1 μβ for the 8c site. The electron transitions that generate the absorption edge of the compound are characterized by d-d transitions of Fe3+(1,2) at 12d and 8c sites, which agree with the experimental. The calculated value of the static dielectric constant (ω → 0), obtained from calculation of refractive index, is 1.66.