The G0W0 band gap of ZnO: effects of plasmon-pole models

Carefully converged calculations are performed for the band gap of ZnO within the G0W0 approximation. The results obtained using four different well-established plasmon-pole models are compared with those of explicit calculations without such models (the contour-deformation approach). We evaluate the difference between plasmon-pole models that enforce the f-sum rule and those that are fitted to reproduce the low energy response. In the case of ZnO, plasmon-pole models enforcing the f -sum rule underestimate the low-frequency region of the dielectric function probably because of the presence of semi-core states in these calculations. Our results confirm that the band gap of ZnO is underestimated in the G0W0 approach as compared to experiment.