Application of attractive potential by DFT + U to predict the electronic properties of materials without highly localized bands AITranslate

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DOI：https://doi.org/10.1016/j.commatsci.2013.08.031

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Highlights • Find and justify an economical but reasonable method to study materials like GaP. • Lack of attractive interaction in p-bands results in the poor results of GaP by DFT. • DFT + U method is applied to supply additional attractive correlations to p-bands. • This induced self-interaction corrections and increased the covalency of the bonds. • Effective masses have been used as a measure of localization of bands. It is well known that density functional theory (DFT) underestimates band gaps of materials which have highly localized valence electrons. On the other hand, the predictions of electronic properties of materials, which do not have localized band near the band gap, by DFT are not accurate enough as well. The effect of electronic correlation on properties of this second group of materials such as, in particular, gallium phosphide (GaP) is theoretically studied in this paper. The goal is to find and physically justify a computationally economical but reasonably accurate method to study such materials. The electronic correlation in GaP has been varied by using DFT based methods, such as in DFT + U, with different U-values for gallium d and phosphorus p orbitals. The fact that GaP does not have partially filled localized orbitals, such as 3d orbitals in ZnO, the justification for the use of DFT + U is rather challenging. DFT + U method, as is applied here in an unconventional way to include attractive potentials, correct the shortcoming of DFT in a very economical way by improving both the band gap and mechanical properties. These results will facilitate large supercell calculations for doping or alloying in GaP or similar materials. Graphical abstract Electron density obtained for GaP at (a) U = 0 eV and (b) U = −12 eV on P p-orbital. The center atom is P and the three outer atoms are Ga. The inflated charge density for U = −12 eV at the Ga–P bonds indicate the increased hybridization at these bonds due to the application of negative U. The arrows on the top Ga–P bond just highlight the change of width of charge densities due to this effect. All three bonds seen here show similar effect. Download : Download high-res image (128KB) Download : Download full-size image