On the origin of single spin centers in hexagonal boron nitride

The coherently addressable single spins in two-dimensional materials such as h-BN may be the building block of ultrasensitive quantum sensors and quantum simulation devices. Recently, quantum emitting sources embedded within hexagonal boron nitride (h-BN) exhibiting optical magnetic resonance (ODMR) have been reported with isotropic g-factor and vanishing zero-field splitting [1]. Here we report strongly accumulating evidence from the results of density functional theory calculations on point defects in h-BN, based on the comparison of the observed and computed zero-phonon-line, phonon sideband in the emission, and the broadening of the ODMR line due to hyperfine interaction with the host nuclear spins, that one of the single spin centers is the carbon impurity substituting the boron site. We discuss the role of other carbon related defects in h-BN as the candidates for the other observed single spin centers.

[1] N Chejanovsky et al., arXiv:1906.05903