Recently the point defect responsible for the intra-3d luminescence of cobalt in doped ZnO samples has been indentified\,\cite{pssb2019}. In this work we further extend our investigation to other point defects in Co-doped ZnO. We use density-functional theory and GW calculations to determined the orbital-resolved band structure of cobalt doped zinc oxide (ZnO). We show that mainly O-p and Co-d orbitals take part in the process and confirm that an oxygen interstitial nearby a cobalt atom is a likely defect to occur in Co-implanted ZnO samples. We also rule out that other common point defects in ZnO can be responsible for the observed intra-3d transition. Finally, we suggest that defect complexes involving oxygen interstitials could be used to promote ferromagnetism in cobalt doped ZnO samples.
@article{arxiv.1908.04679,
title = {GW electronic structure calculations of Co doped ZnO},
author = {Dennis Franke and Michael Lorke and Thomas Frauenheim and A. L. da Rosa},
journal= {arXiv preprint arXiv:1908.04679},
year = {2020}
}