Spin-dependent photodynamics of boron-vacancy centers in hexagonal boron nitride Auteur(s): Clua-Provost T., Mu Z., Durand A., Schrader C., Happacher J., Bocquel J., Maletinsky P., Fraunié J., Marie X., Robert C., Seine G., Janzen E., Edgar J., Gil B., Cassabois G., Jacques V. (Article) Publié: Physical Review B, vol. 110 p.014104 (2024) Ref HAL: hal-04797955_v1 DOI: 10.1103/PhysRevB.110.014104 Exporter : BibTex | endNote Résumé: The negatively-charged boron vacancy (V - B ) center in hexagonal boron nitride (hBN) is currently garnering considerable attention for the design of two-dimensional (2D) quantum sensing units. Such developments require a precise understanding of the spin-dependent optical response of V - B centers, which still remains poorly documented despite its key role for sensing applications. Here we investigate the spin-dependent photodynamics of V - B centers in hBN by a series of time-resolved photoluminescence (PL) measurements. We first introduce a robust all-optical method to infer the spin-dependent lifetime of the excited states and the electron spin polarization of V - B centers under optical pumping. Using these results, we then analyze PL time traces recorded at different optical excitation powers with a seven-level model of the V - B center and we extract all the rates involved in the spin-dependent optical cycles, both under ambient conditions and at liquid helium temperature. These findings are finally used to study the impact of a vector magnetic field on the optical response. More precisely, we analyze PL quenching effects resulting from electron spin mixing induced by the magnetic field component perpendicular to the V - B quantization axis. All experimental results are well reproduced by the seven-level model, illustrating its robustness to describe the spin-dependent photodymanics of V - B centers. This work provides important insights into the properties of V - B centers in hBN, which are valuable for future developments of 2D quantum sensing units. |