MOLECULAR-DYNAMICS STUDY OF THE DISPLACEMENT THRESHOLD SURFACES AND THE STABILITY OF FRENKEL PAIRS IN BETA-SIC

The displacement energy threshold surfaces of Si and C atoms in beta-SiC are determined using the molecular dynamics (MD) technique. Average displacement energies of 92.6 and 16.3 eV are calculated for Si and C atoms, respectively. Phase space analysis is used to determine Frenkel pairs separations and to study the effects of the pka initial energy and the initial crystal temperature on the stability of defects produced, within the framework of the nonlinear dynamics theory of systems of many degrees of freedom. For Si pkas a slight decrease in the displacement threshold energies is observed as the initial crystal temperature increases from 10 to 100 K. For C pkas no significant changes in displacement energies are observed. Channeling of C atoms along the [110] direction is observed to be the only mechanism of producing Frenkel pairs of large separation.