Ab initio study of point defect structures and energetics in ZrC

The potential use of ZrC for nuclear applications in irradiated environments makes it important to determine the structure and energetics of its point defects. In this paper the structures and energies of potential vacancy and interstitial point defects are examined by means of ab initio calculations. It is shown that C vacancies are easily formed and that their ab initio energetics are consistent with thermodynamic models of phase stability of the off-stoichiometric $ZrCx$ $(x<1)$ material. C interstitials are shown to be the most stable interstitial defect and form a C–C–C trimer along the $⟨101⟩$ direction. C vacancies and interstitials are found to be dramatically more stable than antisite defects or Zr vacancies or interstitials.