First Principles Modeling of BaCeO 3: Stabilization of O Vacancies

摘要: We use first-principles density functional theory (DFT) calculations to investigate the ground state structures of both BaCeO 3 (BC) and Pd-doped BC (BCP) perovskites of general formula ABO 3. The relaxed structures match closely with recent experimental scattering studies, and also provide a local picture of how the BC perovskite lattice accommodates Pd. Both stoichiometric and oxygen-deficient materials are considered, and structures with an O vacancy adjacent to each Pd are predicted to be favored. The oxidation state of Pd in each doped structure is investigated through a structural analysis, the results of which are supported by an orbital-resolved projected density of states. The local bonding environments around Pd as well as the electron fillings of atomic orbitals on Pd and its neighbors are examined. A particular focus is the character of the highest occupied molecular orbital (HOMO) and the few lowest …