QUANTUM INFORMATICS. QUANTUM INFORMATION PROCESSORS QuantumChemical Modeling of Structural, Electronic, and Spin Characteristics of NV Centers in Nanostructured Diamond: Surface Effect

Abstract —The effect of the surface of diamond on atomic, electronic, and spin properties of diamondnanocrystals containing single nitrogen–vacancy defects ( [NV] – centers) is studied. The surface was modeledwith clusters C 33 H 30 [NV] – , C 66 H 72 [NV] – , which were constructed based on bulk clusters C 33 H 36 [NV] – andC 69 H 84 [NV] – , respectively. In all cases, clusters in the triplet state S = 1 are considered with the cluster chargebeing –1. The geometric structure of clusters is optimized using the principle of minimization of the totalenergy of the system; then, the electronic and spin characteristics of clusters are calculated by the densityfunctional theory. The isotropic and anisotropic hyperfine interaction constants of the electron spin of theNV center with the nuclear spi n of the nitrogen atom and 13 C atoms located at different sites in the cluster arecalculated. It is found that, in contrast to bulk clusters with [NV] – centers in which the spin density is mainlylocalized at the three carbon atoms that are the neares t neighbors of the vacancy of the center, upon arrangement of the NV center in the immediate proximity to th e surface, the spin density is redistributed such that itis mainly localized at the three carbon atoms that are the nearest neighbors of the nitrogen atom of the centerand at C atoms that form the first atomic layer of the (111) surface of the nanocrystal.