Please cite the following references:
 Luiz G. Ferreira, Marcelo Marques, and Lara K. Teles, "Approximation to density functional theory for the calculation of band gaps of semiconductors", Physical Review B 78, 125116 (2008).
 Ge-Qi Mao, Zhao-Yi Yan, Kan-Hao Xue, Zhengwei Ai, Shengxin Yang, Hanli Cui, Jun-Hui Yuan, Tian-Ling Ren, and Xiangshui Miao, "DFT-1/2 and shell DFT-1/2 methods: electronic structure calculation for semiconductors at LDA complexity", Journal of Physics: Condensed Matter 34, 403001 (2022).
For information and references for the VASP code, please visit: http://www.vasp.at
The self-energy potentials were generated by atom/ion calculations using ATOM, a program for DFT calculations in atoms and pseudopotential generation, maintained by Alberto Garcia.