Prediction of threshold displacement energies in TiC by ab initio molecular dynamics simulation method
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The ab-initio molecular dynamics (AIMD) simulation method is used to compute the threshold displacement energies (Ed) of the Ti atom and the C atom in TiC. The Ed is calculated along the three high symmetric crystallographic directions, namely, [100], [110], and [111] and the weighted average of Ed is found to be 33 eV and 32 eV for Ti and C sublattice, respectively. The effect of small deviations from the high symmetry directions is also studied and the weighted average value of Ed along the 2◦ off-symmetric directions is found to be 35 eV for both the Ti atom and the C atom. Furthermore, the values of Ed are calculated in the presence of vacancies in C sites, which are often encountered in TiCx. In this case, small increases in the magnitude of weighted average values of Ed are observed, and these are found to be 39 eV and 34 eV for Ti and C, respectively. Anti-site defects are formed in all cases of Ti primary knock-on atom (PKA), however, no anti-site defect is formed along the high symmetry direction for C PKA. The calculated Ed values are explained by the structural and chemical properties of TiC. The projected values of Ed would be valuable parameters for modeling irradiation damage in TiC.
Abstract
The ab-initio molecular dynamics (AIMD) simulation method is used to compute the threshold displacement energies (Ed) of the Ti atom and the C atom in TiC. The Ed is calculated along the three high symmetric crystallographic directions, namely, [100], [110], and [111] and the weighted average of Ed is found to be 33 eV and 32 eV for Ti and C sublattice, respectively. The effect of small deviations from the high symmetry directions is also studied and the weighted average value of Ed along the 2◦ off-symmetric directions is found to be 35 eV for both the Ti atom and the C atom. Furthermore, the values of Ed are calculated in the presence of vacancies in C sites, which are often encountered in TiCx. In this case, small increases in the magnitude of weighted average values of Ed are observed, and these are found to be 39 eV and 34 eV for Ti and C, respectively. Anti-site defects are formed in all cases of Ti primary knock-on atom (PKA), however, no anti-site defect is formed along the high symmetry direction for C PKA. The calculated Ed values are explained by the structural and chemical properties of TiC. The projected values of Ed would be valuable parameters for modeling irradiation damage in TiC.