Toward a Consistent Prediction of Defect Chemistry in CeO2

Polarizable shell-model potentials are widely used for atomic-scale modeling of charged defects in solids using the Mott-Littleton approach and hybrid Quantum Mechanical/ Molecular Mechanical (QM/MM) embedded-cluster techniques. However, at the pure MM level of theory, the calculated defect energetics may not satisfy the requirement of quantitative predictions and are limited to only certain charged states. Here, we proposed a novel interatomic potential development scheme that unifies the predictions of all relevant charged defects in CeO2 based on the Mott-Littleton approach and QM/MM electronic -structure calculations. The predicted formation energies of oxygen vacancies accompanied by different excess electron localization patterns at the MM level of theory reach the accuracy of density functional theory (DFT) calculations using hybrid functionals. The new potential also accurately reproduces a wide range of physical properties of CeO2, showing excellent agreement with experimental and other computational studies. These findings provide opportunities for accurate large-scale modeling of the partial reduction and nonstoichiometry in CeO2, as well as a prototype for developing robust interatomic potentials for other defective crystals.

Automated summary

In this paper, a new interatomic potential development scheme is proposed, which unifies the predictions of all relevant charged defects in CeO2 based on the Mott-Littleton approach and QM/MM electronic structure calculations. The accuracy of defect energetics at the pure MM level of theory reaches that of density functional theory (DFT) calculations, and a wide range of physical properties of CeO2 are accurately reproduced.