title: Theoretical description of carrier mediated magnetism in cobalt doped ZnO.
abstract: Substitutional cobalt in ZnO has a weak preference for antiferromagnetic ordering. Stabilization of ferromagnetism is achieved through n-type doping, which can be understood through a band coupling model. However, the description of the transition to a ferromagnetic ground state varies within different levels of band theory; issues arise due to the density functional theory underestimation of the band gap of ZnO, and the relative position of the nominally unfilled Co t{2d} states. We examine these limitations, including approaches to overcome them, and explain the contradictions in previous studies, which drastically overestimate the doping threshold for magnetic ordering.
authors.affiliation: National Renewable Energy Laboratory, Golden, Colorado 80401, USA.
authors.forename: Aron
authors.initials: A
authors.lastname: Walsh
authors.forename: Juarez L F
authors.initials: JL
authors.lastname: Da Silva
authors.forename: Su-Huai
authors.initials: SH
authors.lastname: Wei