Fig. 1: Observation of three types of single spin defect in hBN.
From: Single nuclear spin detection and control in a van der Waals material
a, Illustration of a carbon-related spin defect complex, consisting of an electron spin strongly coupled to a 13C nuclear spin and a nearby, weakly coupled electron spin without strong hyperfine interaction. b, PL confocal map showing isolated bright emitters in hBN. Scale bar, 2 μm. c, Energy-level diagram of an electron spin S = 1/2, coupled to a 13C nuclear spin (I = 1/2). Azz is the hyperfine interaction strength. ν1,e and ν2,e are the two electron spin transitions. d–f, Optical spectra of defects 1–3, belonging to groups I–III, respectively. g–i, ODMR spectra of defects 1–3 under an out-of-plane external magnetic field of 62.5 mT. The number of peaks in the central region (shaded area) differs among groups I–III defects. Within this shaded area, the peaks correspond to the |−1/2⟩ ↔ |+1/2⟩ transitions, with hyperfine structures observed in groups II and III. Outside the shaded region, the transitions correspond to the |0⟩ ↔ |±1⟩ transitions. Furthermore, the defect in h exhibits a |−1⟩ ↔ |+1⟩ double-quantum transition (II-5). j, Illustration of the spin-pair model for explaining the coexistence of S = 1 and S = 1/2 transitions. k,l, Magnetic-field-dependent ODMR spectra of defect 2 in group II (k) and defect 3 in group III (l). a.u., arbitrary units.
