Effect of cationic chemical disorder on defect formation energies in uranium–plutonium mixed oxides

At the atomic scale, uranium–plutonium mixed oxides (U,Pu)O 2 are characterized by cationic chemical disorder, which entails that U and Pu cations randomly distributed on cation sublattice. In present work, we study impact of disorder point defect formation energies in using interatomic-potential density functional theory (DFT + U) calculations. We focus bound Schottky defects (BSD) among most stable these oxides. As a first step, estimate distance R D around BSD up to local environment significantly affects their energy. To this end, propose an original procedure energy is computed for several supercells at varying levels . conclude three shells have non-negligible influence [Formula: see text]. apply then systematic approach compute all possible configurations second nearest neighbor BSD. show can range interval 0.97 eV, depending relative amount neighboring cations. Based results, interaction model describes effect nominal composition Finally, DFT benchmark calculations satisfactory agreement U-rich larger mismatch case Pu-rich one. summary, work provides valuable insights properties represent valid strategy disordered compounds.