title: Quasiparticle band gap of ZnO: high accuracy from the conventional G⁰W⁰ approach.
abstract: Contrary to previous reports, we show that the conventional GW (the so-called G⁰W⁰) approximation can be used to calculate accurately the experimental band gap (∼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.
authors.affiliation: Department of Physics, University at Buffalo, SUNY, Buffalo, New York 14260, USA.
authors.forename: Bi-Ching
authors.initials: BC
authors.lastname: Shih
authors.forename: Yu
authors.initials: Y
authors.lastname: Xue
authors.forename: Peihong
authors.initials: P
authors.lastname: Zhang
authors.forename: Marvin L
authors.initials: ML
authors.lastname: Cohen
authors.forename: Steven G
authors.initials: SG
authors.lastname: Louie