Density functional theory study of iron defects in diamond

Diamond is known to incorporate a range of impurities, either during growth or subsequently by diffusion or implantation. Transition metals, such as Co and Ni, are known to form point defects in high-temperature–high-pressure growth from the solvent-catalyst, but other transition metal species present in the environment during growth appear not to become incorporated in a way that can be detected as stable, grown-in centres, although there is some experimental evidence that Fe might be incorporated in defect complexes, and any impurity might be added by implantation. In this report, we present the results of first principles simulations of Fe-containing defect centres, including the complexes with native defects and other common impurities. We find that interstitial Fe is unstable, but substitional Fe along with its complexes with other defects provide a wide range of observable properties. In particular, complexes with vacancies show interesting electronic structures that might be suited to defect-based applications including single-photon sources and magnetometry.