The LDA + U approach could be used essentially as a shift potential to open up the band gap of a semiconductor. This approach was previously applied to the oxygen vacancy in ZnO (Paudel and Lambrecht, 2008). Here, the results of that approach were reviewed and additional refinements of the LDA + U model were introduced. Good agreement was obtained with recent hybrid functional calculations on the position of the ε(2ǂ/0) transition state. A comparison of various approaches on the oxygen vacancy in ZnO was provided. The relevance of the one-electron levels to the experiments was considered.

Critical Evaluation of the LDA + U Approach for Band Gap Corrections in Point Defect Calculations: the Oxygen Vacancy in ZnO Case Study. Boonchun, A., Lambrecht, W.R.L.: Physica Status Solidi B, 2011, 248[5], 1043–51