Molecular Dynamic Simulation for the NV-N Center Formation by Means of N<sub>2</sub> Beam Implantation into a Diamond

Abstract

We have searched for an optimum condition to form a specific defect center called NY-N (nitrogen-vacancy-nitrogen) in a diamond, which is of interest, because of the possibility of a NOT system in a quantum computer. It is composed of one NV center made of a substitutional nitrogen (N) coupled with an adjacent vacancy (V) and an associated N atom. The second N is located at a mean distance (RN-N) of ~ 2 nm. Considering the cohesive potentials we performed an empirical molecular dynamic simulation for the low-energy N2 beam implantation into a diamond. The identification of a NV center was performed by a crystallographic analysis called the pixel-mapping (PM) method based on crystallography. We found that impact energy Eo could be decisive for the mean distance RN.N, while temperature T was decisive for the formation ofNY centers. The optimum set of conditions to form an NV-N center is a compromising choice of (Eo, T). The formation probability of the NY center exceeded 20 % when using (Eo, T) = (200 (eV/atom), 1000 K), however, the mean value was below 1.5 nm. A 1ittle higher energy than 200 (eV/atom) will be necessary for ideal NV-N centers.