Molecular dynamics study of the threshold displacement energy in MgO

Molecular dynamics (MD) simulations were used to obtain threshold displacem ent energies (Ed) of atoms along specific directions in MgO. In the simulat ion, an atom in the center of the cell was given kinetic energy along a spe cific crystallographic direction. The positions and site potential energies of the primary knock-on atom (pka) and all neighboring atoms were monitore d as a function of time. In this work, the minimum displacement energies th at formed stable Frenkel pair defects were determined to be 90 +/- 2 eV alo ng the [131] direction for magnesium and 67 +/- 3 eV along the [121] direct ion for oxygen. The MD simulations reveal that atomic displacement events c onsist of replacement collision sequences in addition to the production of Frenkel pairs. (C) 2000 Elsevier Science B.V, All rights reserved.