title: Defective α-Fe2O3(0001): an ab initio study.
abstract: By using density functional theory calculations at the PBE+U level, we investigated the properties of hematite (0001) surfaces decorated with adatoms/vacancies/substituents. For the most stable surface termination over a large range of oxygen chemical potentials (muO), the vacancy formation and adsorption energies were determined as a function of muO. Under oxygen-rich conditions, all defects are metastable with respect to the ideal surface. Under oxygen-poor conditions, O vacancies and Fe adatoms become stable. Under ambient conditions, all defects are metastable; in the bulk, O vacancies form more easily than Fe vacancies, whereas at the surface the opposite is true. All defects, that is, O and Fe vacancies, Fe and Al adatoms, and Al substituents, induce important modifications to the geometry of the surface in their vicinity. Dissociative adsorption of molecular oxygen is likely to be exothermic on surfaces with Fe/Al adatoms or O vacancies.
authors.affiliation: The Abdus Salam International Centre for Theoretical Physics, Strada Costiera 11, 34151 Trieste (Italy). mtnguyen@ictp.it.
authors.forename: Manh-Thuong
authors.initials: MT
authors.lastname: Nguyen
authors.forename: Nicola
authors.initials: N
authors.lastname: Seriani
authors.forename: Ralph
authors.initials: R
authors.lastname: Gebauer
keywords: ab initio calculations; adsorption; hematite; oxygen; surface chemistry