A density functional theory study of oxygen-vacancy complexes in diamond

Abstract

        This study investigates the properties of oxygen-vacancy and –divacancy defects in diamonds using ab initio density-functional theory. Oxygen-vacancy (O-V) and oxygen-divacancy (O-V₂) complexes are modeled to understand their electronic structure, stability, and potential correlation with known electron paramagnetic resonance (EPR) centers. The O-V complex is iso-electronic to the well-studied nitrogen-vacancy (NV)^-1 center, exhibits C_3v symmetry and a spin-1 ground state. Calculated hyperfine tensors for ¹⁷O and neighboring ¹³C atoms are compared with experimental data from the EPR center called WAR5, suggesting a possible association. For the O-V₂ complex, the V-O-V arrangement is found to be more stable than V-V-O by 0.3 eV, with a spin-1 ground state and C_2v symmetry. While V-O-V shares some similarities with the EPR center called R5. These findings provide insights into the atomic structure and properties of oxygen-related defects in diamond, which are of interest for quantum information and sensing applications.