We report on electron spin resonance (ESR) spectroscopy of boron-vacancy (VB−) centers hosted in isotopically-engineered hexagonal boron nitride (hBN) crystals. We first show that isotopic purification of hBN with 15N yields a simplified and well-resolved hyperfine structure of VB− centers, while purification with 10B leads to narrower ESR linewidths. These results establish isotopically-purified h10B15N crystals as the optimal host material for future use of VB− spin defects in quantum technologies. Capitalizing on these findings, we then demonstrate optically-induced polarization of 15N nuclei in h10B15N, whose mechanism relies on electron-nuclear spin mixing in the VB− ground state. This work opens up new prospects for future developments of spin-based quantum sensors and simulators on a two-dimensional material platform.
@article{arxiv.2307.06774,
title = {Isotopic control of the boron-vacancy spin defect in hexagonal boron nitride},
author = {T. Clua-Provost and A. Durand and Z. Mu and T. Rastoin and J. Fraunié and E. Janzen and H. Schutte and J. H. Edgar and G. Seine and A. Claverie and X. Marie and C. Robert and B. Gil and G. Cassabois and V. Jacques},
journal= {arXiv preprint arXiv:2307.06774},
year = {2023}
}