Microscopic picture of Co clustering in ZnO

Citation Iusan, Diana et al. " Microscopic picture of Co clustering in ZnO. Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. Density functional theory was applied to study the chemical and magnetic interactions between Co atoms doped in ZnO. It was found that the Co impurities tend to form nanoclusters and the interactions between these atoms are antiferromagnetic within the local spin-density approximation ͑LSDA͒ + Hubbard U approach. The extracted interatomic exchange parameters agree reasonably well with recent experimental results. We have analyzed and compared the electronic structure obtained using the LSDA and LSDA+ U approaches and found that the LSDA+ U gives the most reasonable result, highlighting the importance of short-ranged antiferromag-netic interactions due to superexchange.