LAUSR

Abstract The effects of including the Hubbard on-site Coulombic correction to the structural parameters and valence energy states of wurtzite ZnO were explored. Due to the changes in the structural parameters caused by correction of hybridization between Zn d states and O p states, suitable parameters of Hubbard terms have to be determined for an accurate prediction of ZnO properties. Using the LDA + U method by applying Hubbard corrections Ud to Zn 3d states and Up to O 2p states, the lattice constants were underestimated for all tested Hubbard parameters. The combination of both Ud and Up correction terms managed to widen the band gap of wurtzite ZnO to the experimental value. Pairs of Ud and Up parameters with the correct positioning of d-band and accurate bandwidths were selected, in addition to predicting an accurate band gap value. Inspection of vibrational properties, however, revealed mismatches between the estimated gamma phonon frequencies and experimental values. The selection of Hubbard terms based on electronic band properties alone cannot ensure an accurate vibrational description in LDA + U calculation.