Narrow Inhomogeneous Distribution and Charge State Stabilization of Lead‐Vacancy Centers in Diamond

Abstract Lead‐vacancy (PbV) centers in diamond with a large ground state splitting are expected to be a building block of quantum network nodes. Due to the heaviness of the Pb atom, it is challenging to fabricate high‐quality PbV centers with a narrow inhomogeneous distribution and stable charge state. In this study, for the formation of the PbV centers, high‐temperature anneal up to 2300 °C is performed after Pb ion implantation. At a lower temperature of 1800 °C, the PbV centers show a large inhomogeneous distribution and spectral diffusion, while higher temperatures of 2200–2300 °C leads to narrow inhomogeneous distributions with standard deviations of ≈5 GHz. The charge state transition of the PbV centers formed at 2200 °C occurs by capturing photo‐carriers generated from surrounding defects under 532 nm laser irradiation. Finally, multiple stable PbV centers with nearly identical photon frequencies are obtained, which is essential for applications in quantum information processing.