An efficient method of DFT/LDA band-gap correction

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• 作者：Pawel Scharoch ; Maciej Winiarski
• 关键词：DFT/LDA band-gap ; Semiconductor alloy ; VCA ; Electron localization
• 刊名：Computer Physics Communications
• 出版年：December, 2013
• 年：2013
• 卷：184
• 期：12
• 页码：2680-2683
• 全文大小：396 K

文摘

It has been shown that the underestimated by DFT/LDA(GGA) band-gap can be efficiently corrected by an averaging procedure of transition energies over a region close to the direct band-gap transition, which we call the method (the differences in the Kohn-Sham eigenvalues). For small excitations the averaging appears to be equivalent to the approach (differences in the self-consistent energies), which is a consequence of Janak鈥檚 theorem and has been confirmed numerically. The Gaussian distribution in -space for electronic excitation has been used (occupation numbers in the or eigenenergy sampling in the ). A systematic behavior of the -space localization parameter correcting the band-gap has been observed in numerical experiments. On that basis some sampling schemes for band-gap correction have been proposed and tested in the prediction of the band-gap behavior in semiconducting alloy, and a very good agreement with independent calculations has been obtained. In the context of the work the issue of electron localization in the -space has been discussed which, as it has been predicted by Mori-S谩nchez et聽al. [P. Mori-S谩nchez, A.J. Cohen, W. Yang, Phys. Rev. Lett. 100 (2008) 146401], should reduce the effect of the convex behavior of the LDA/GGA functionals and improve the band-gap prediction within DFT/LDA(GGA). A scheme for electron localization in -space has been suggested.