Figure 8
Sink efficiences as calculated using OKMC for (a) “free surface” boundary conditions and (b) periodic boundary conditions. In both (a) and (b), the sink efficiency is given as a function of the binding energy of vacancies to the GB and the migration energy of defects (interstitials in (a) and vacancies in (b)) within the GB. See text for details. (c–d) The concentration of vacancies at and near the GB for (c) the periodic model and (d) the “free surface” model. The different cases represent different defect energetics. Case 1: migration barrier for vacancy is 2.0 eV, binding energy of vacancy is 0.28 eV, mobility of interstitial is 0; Case 2: migration barrier for vacancy is 0.4 eV, binding energy of vacancy is −1.32 eV, mobility of interstitial is 0; Case 3: migration barrier for vacancy is 0.68 eV, binding energy of vacancy is 0.28 eV, migration barrier of interstitial is 2.0 eV; Case 4: migration barrier for vacancy is 0.68 eV, binding energy of vacancy is −1.32 eV, migration barrier of interstitial is 0.4 eV.
