DFT-1/2 and shell DFT-1/2 methods: electronic structure calculation for semiconductors at LDA complexity. (5th October 2022)

• Record Type: Journal Article
• Authors: Mao, Ge-Qi; Yan, Zhao-Yi; Xue, Kan-Hao; Ai, Zhengwei; Yang, Shengxin; Cui, Hanli; Yuan, Jun-Hui; Ren, Tian-Ling; Miao, Xiangshui
• Is Part Of: Journal of physics. Volume 34:Number 40(2022)
• Publication Date: 2022-10-05
• Subjects: DFT-1/2 -- shell DFT-1/2 -- band gap -- semiconductor -- electronic structure calculation -- density functional theory -- self-energy correction; Condensed matter -- Periodicals; Matière condensée -- Périodiques; Vaste stoffen; Vloeistoffen; Natuurkunde; Electronic journals; Computer network resources; 530.4105
• DOI: 10.1088/1361-648X/ac829d
• Languages: English
• ISSNs: 0953-8984

Abstract

Abstract: It is known that the Kohn–Sham eigenvalues do not characterize experimental excitation energies directly, and the band gap of a semiconductor is typically underestimated by local density approximation (LDA) of density functional theory (DFT). An embarrassing situation is that one usually uses LDA+ U for strongly correlated materials with rectified band gaps, but for non-strongly-correlated semiconductors one has to resort to expensive methods like hybrid functionals or GW . In spite of the state-of-the-art meta-generalized gradient approximation functionals like TB-mBJ and SCAN, methods with LDA-level complexity to rectify the semiconductor band gaps are in high demand. DFT-1/2 stands as a feasible approach and has been more widely used in recent years. In this work we give a detailed derivation of the Slater half occupation technique, and review the assumptions made by DFT-1/2 in semiconductor band structure calculations. In particular, the self-energy potential approach is verified through mathematical derivations. The aims, features and principles of shell DFT-1/2 for covalent semiconductors are also accounted for in great detail. Other developments of DFT-1/2 including conduction band correction, DFT+ A -1/2, empirical formula for the self-energy potential cutoff radius, etc, are further reviewed. The relations of DFT-1/2 to hybrid functional, sX-LDA, GW, self-interaction correction, scissor's operator as well as DFT+ U are explained. Applications, issues and limitations of DFT-1/2 are comprehensively included in this review.