First-principles calculations of optical and positron annihilation properties of NV center in 3C-SiC C-SiC

We studied the optical and positron annihilation properties of N(C)V(S)i in 3C-SiC using first-principles calculations. We found that the charge-state transition and the spin-conserving optical transition levels are very close to each other. In order to distinguish between the NV center and intrinsic defect, we calculate in detail the defect formation energies, temperature-dependent positron lifetimes, and electron-positron momentum distribution of these defects in 3C-SiC. We suggest that using positrons technique alone is insufficiently sensitive in identifying the charge-states of N(C)V(S)i, necessitating the use of additional characterization methods to address this issue.