Extended Data Fig. 1: Spin-pair model.
From: Single nuclear spin detection and control in a van der Waals material
a, Two possible electron configurations of a spin defect complex in different internal charge states. b, The energy levels of internal charge states according to the DFT prediction. When two electrons occupy the same defect site (left), it forms a singlet GS and ES, as well as a triplet metastable state. When two electrons locate at different defect sites (right), each form a S = 1/2 state and they are weakly coupled through dipolar interaction, forming a spin S = 1/2 pair. c, A proposed energy-level diagram for explaining the coexistence of the S = 1/2 and S = 1 ODMR transitions.
