Systematic investigation of dynamic nuclear polarization with boron vacancy in hexagonal boron nitride

The authors present here a systematic investigation of dynamic nuclear polarization (DNP) using the negatively charged boron vacancy (${\mathrm{V}}_{\mathrm{B}}^{\ensuremath{-}}$) in hBN. They measure optically detected magnetic resonance (ODMR) spectra across a wide magnetic field range, including the ground state level anticrossing, and develop Lindblad-based simulations with a single electron spin and three ${}^{15}\mathrm{N}$ nuclear spins. The results reveal limitations of standard fitting methods and symmetry-induced constraints on maximum nuclear polarization.