Simulation of interstitial atoms in two-dimensional nanocrystals

The molecular-dynamics method is used to study the emergence of interstitial atoms at a free face of a 2D nanocrystal. Two new types of coordination of the interstitial defect are discovered: a symmetric trifolium coordination and a linear coordination of compressed atoms. It is shown that, in the case of linear coordination, a dislocation dipole is formed in the 2D crystal lattice; the dipole is characterized by a high mobility facilitating the arrival of an interstitial atom at a free face of the crystal. The cases of transition of an interstitial atom from one type of coordination to another, depending on the crystal temperature, are studied in a computer experiment.