title: Electronic correlation in anion p orbitals impedes ferromagnetism due to cation vacancies in Zn chalcogenides.
abstract: 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).
authors: National Renewable Energy Laboratory, Golden, Colorado 80401, USA.
authors: J A
authors: JA
authors: Chan
authors: Stephan
authors: S
authors: Lany
authors: Alex
authors: A
authors: Zunger