Quasiparticle Band Gap of ZnO: High Accuracy from the Conventional G0W0 Approach

Contrary to previous reports, we show that the conventional GW (the so-called G(0)W(0)) approximation can be used to calculate accurately the experimental band gap (similar to 3.6 eV) of ZnO. The widely discussed underestimate of the quasiparticle gap of ZnO within the GW method is a result of an inadequate treatment of the semicore electrons and the slow and nonuniform convergence in the calculation of the Coulomb-hole self-energy in previous studies. In addition, an assumed small kinetic energy cutoff for the dielectric matrix may result in a false convergence behavior for the quasiparticle self-energy.