First-principles study of impurities on diamond surfaces

Nitrogen-vacancy (NV) centers in diamond are used for quantum sensing applications. For this purpose NV centers need to be close to the diamond surface. Experimentally it is observed that the coherence time decreases as the depth of NV centers decreases. Unpaired electronic spins on the diamond surface can lead to decoherence of the NV centers, but the origin of these unpaired spins is not known. We focus on the hydrogen terminated diamond (100) surface and perform density functional theory calculations to study the electronic properties of impurities on diamond surfaces, including Cl, Si, N, and Na, which are common impurities that can be introduced during growth, processing, or surface treatment. We discuss the origin of localized spins, and the origin of diamond surface states and effects of different surface terminations.