Screened hybrid and self-consistentGWcalculations of cadmium/magnesium indium sulfide materials

Abstract

The cadmium and magnesium indium sulfides are medium-gap semiconductors demonstrating a propensity to form intermediate band materials when doped with transition metals. The inherent structural diversity exhibited by M +2 In2S4 thiospinels and related AB2X4 compounds often preclude definitive experimental determination of the band gap width and type of transition. Employing a series of traditional semi-local functionals (LDA, PBE, TPSS) and the screened hybrid HSE, band gaps, projected densities of states and band structures are calculated for the normal, full inverse and intermediate configurations of [Cd/Mg]8In16S32. Band structures and band gaps are also obtained via self-consistent many-body methods, using the static Coulomb-hole and screened exchange approximation to GW as a starting point for perturbative G0W0 calculations. Comparison to experiment indicates that HSE provides an accurate, computationally-efficient and relatively rapid means for predicting band gap properties in spinel-type photovoltaic materials.

V-substituted In2S3: an intermediate band material with photocatalytic activity in the whole visible light range

“…2.2 eV. It is however close to that found for unsubstituted MgIn 2 S 4 in a similar sc-COHSEX + G 0 W 0 calculation, which gave for it a bandgap of 3.04 eV 43 evidencing that the insertion of vanadium in the thiospinel structure does not alter much the intrinsic bandgap in agreement with the mentioned similarity in the position of the main rise in absorption occurring in the experimental optical spectrum. As said in ref.…”

Electronic and optical properties of single crystal SnS2: an earth-abundant disulfide photocatalyst

“…a more rigorous description of many body effects may be required for 2D systems. Our results indicate therefore that in order to recover properties for these 2D systems that are as accurate as possible, more sophisticated implementations of DFT are necessary, for example the self consistent screening approach described by Lucero et al, 52,53 and the explicit treatment of electron-phonon coupling. This is due to the sensitivity of the electronic structure on the VdW spacing that is, as of yet, poorly described, even with modern corrections.…”

Understanding Ti intermediate-band formation in partially inverse thiospinel MgIn2S4through many-body approaches

“…Although there is no clear experimental evidence of excitonic or polaronic effects, the absorption spectra of Ruiz-Fuertes et al 44 seem to be coherent with the presence of excitons, and the large difference € 0 -(€0 = 18.8 to 20.74 and = 5.5 to 5.8) 18,29 is an indication of significant polaronic effects. 26,45 To a lesser extent, the differences between the LDA and the experimental structural parameters, the finite temperature of the experiments, and the presence of defects (mainly Mg vacancies), 29 may contribute to the difference between the band gaps.…”