Large-scale local-density-approximation band gap-corrected GaAsN calculations

The electronic structure of a GaAsN alloy is calculated using a 4096 atom supercell, with a 70 Ry plane wave basis cutoff and Ga atom $\text{3d}$ electrons as valence electrons. The charge density of this supercell is generated by patching the charge density of a small unit cell with the charge density of bulk GaAs. The local-density-approximation band gap error is corrected by modifying the nonlocal pseudopotentials. A localized nitrogen state ${\mathrm{[a}}_1\mathrm{(N)}]$ is obtained,and it plays an important role in the band gap reduction of GaAsN.