First-principles study of interacting nitrogen vacancy centers in diamond

Nitrogen-vacancy (NV) centers in diamond are key qubit candidates and powerful platforms for quantum sensing and quantum information processing. Most experimental and theoretical studies have so far focused on isolated NV centers whose electronic structure, optical cycle, and spin properties are relatively well understood. Multiple interacting NV centers are much less studied, due to their complexity, and they are of great interest, as interactions between defects may give rise to novel mechanisms for quantum control that are not present in isolated, single centers.

We present a first principle computational study of interacting NV centers, investigating their formation energies, vertical excitation energies, and intersystem crossing rates using time-dependent density functional theory [1] and quantum defect embedding theory [2]. We analyze how these properties depend on the separation and relative orientation of the NV centers. Our results advance the understanding of defect-defect interactions in semiconductors at the microscopic level, and they can be used to guide the design of scalable quantum registers and coherent spin networks.