Electronic correlation effects, usually associated with open $d$ or $f$ shells, have so far been considered in $p$ orbitals only sporadically for the localized $2p$ states of first-row elements. We demonstrate that the partial band occupation and the metallic band-structure character as predicted by local density calculations for II-VI materials containing cation vacancies is removed when the correct energy splitting between occupied and unoccupied $p$ orbitals is recovered. This transition into a Mott-insulating phase dramatically changes the structural, electronic and magnetic properties along the entire series (ZnO, ZnS, ZnSe, and ZnTe), and impedes ferromagnetism. Thus, important correlation effects due to open $p$ shells exist not only for first-row ($2p$) elements, but also for much heavier anions like Te ($5p$).

• Received 7 May 2009

DOI:https://doi.org/10.1103/PhysRevLett.103.016404