Fig. 4: Representation of various spin defects.

a Depiction of the structural configuration of a boron vacancy (\({{\rm{V}}}_{B}^{-}\)) defect in hBN. b Zero-field ODMR spectrum of \({{\rm{V}}}_{B}^{-}\), showing resonance dips corresponding to spin transitions within the electronic state (in red), and the ground state (blue)¹¹⁵. c Simplified energy level structure of the \({{\rm{V}}}_{B}^{-}\) center in hBN^115,120. d Photoluminescence (PL) spectrum of an ensemble of carbon-related spin defects within hBN¹⁰⁹. e PL spectrum of an individual carbon-related spin defect. f ODMR of a carbon-related spin defect¹³⁷. g Calculated defect levels of Ti_VV defect in hBN¹⁴⁰. h Energy structure of the Ti_VV defect and their recombination rates. i Room temperature X-band EPR spectra of paramagnetic OB₃ in boron oxynitride (BNO) samples¹⁴³. Figures adapted and reprinted with permission from refs. ^{109,115,137,140,143}. Copyright by Springer Nature^{109,115,137,140} and American Chemical Society¹⁴³