Modeling the atomic and electronic structure of diamond nanocrystals containing [NV]− centers by the density functional method

Abstract

UDC 535.33:548.0 We have used the density functional method to model the atomic and electronic structure of diamond nanocrystals passivated by hydrogen atoms and either not containing defects or containing a single [NV]– center. We have shown that in all cases, after relaxation the nanocrystals are formed as diamond-like structures. We have studied the features of the electronic structure of the nanocrystals. We have analyzed in detail the mechanism for the formation of energy levels in the bandgap due to [NV] – centers. We have established that the optical absorption and fluorescence spectra for the [NV] – centers are mainly associated with transitions of electrons between the highest occupied β orbitals (projection of the electron spin equal to +1/2) and lower unoccupied α orbitals (projection of the electron spin equal to –1/2). The results on the localization and energy position of the states in the bandgap match data obtained for the [NV] – center in bulk diamond.