| Abstract: | n ceria the formation of oxygen vacancies plays a key role. Density functional theory, corrected for on-site Coulomb interactions (DFT+U) provides a reasonable description of oxygen vacancies, but has issues with the U dependence. We present a hybrid HSE06 study of oxygen vacancies in the (110) and (100) ceria surfaces. We find (i) the oxygen vacancy formation energy is larger with hybrid DFT compared with DFT+U, (ii) localised Ce3+ ions form and (iii) the position of the Ce3+ gap state is in good agreement with experiment. Our results provide important information for assessing the reliability of the DFT+U approach |
