Molecular dynamics study of the threshold displacement energy in MgO

Molecular dynamics (MD) simulations were used to obtain threshold displacement energies (Ed) of atoms along specific directions in MgO. In the simulation, an atom in the center of the cell was given kinetic energy along a specific crystallographic direction. The positions and site potential energies of the primary knock-on atom (pka) and all neighboring atoms were monitored as a function of time. In this work, the minimum displacement energies that formed stable Frenkel pair defects were determined to be 90±2 eV along the [1 3 1] direction for magnesium and 67±3 eV along the [1 2 1] direction for oxygen. The MD simulations reveal that atomic displacement events consist of replacement collision sequences in addition to the production of Frenkel pairs