Charge state dynamics of ensemble silicon vacancies in bulk diamond

The manipulation of the charge states of solid-state defects is of importance in applications to quantum technology and precision sensing. Relevant examples include the silicon vacancy (SiV) and nitrogen vacancy (NV) centers in diamond, both of which display non-trivial, partly-understood charge state interconversion pathways. Here we investigate the charge state dynamics of ensemble SiVs in a bulk type 1b diamond using multicolor confocal microscopy. We create photoionized carriers via optical illumination, and track their diffusion by monitoring the charge state of the surrounding defects, changing upon carrier capture. Leveraging electric fields to bias carrier diffusion¹, we show that the preferential dark state of silicon vacancies is SiV^2-, which can convert to a bright SiV^- state upon capturing a free hole. These results are relevant to ongoing efforts aimed at exploiting the properties of SiV centers in diamond as spin qubits or nanoscale probes.

1. Lozovoi, A., Jayakumar, H., Daw, D., Lakra, A. & Meriles, C. A. Probing metastable space-charge potentials in a wide bandgap semiconductor. Phys. Rev. Lett. 125, 256602 (2020).