title: Electron localization in defective ceria films: a study with scanning-tunneling microscopy and density-functional theory.
abstract: Scanning-tunneling microscopy and density-functional theory have been employed to identify the spatial correlation between an oxygen vacancy and the associated Ce(3+) ion pair in a defective CeO(2)(111) film. The two Ce(3+) ions can occupy different cationic shells around the vacancy. The resulting variation in the chemical environment leads to a splitting of the filled Ce(3+) f levels, which is detected with STM spectroscopy. The position of the Ce(3+) ion pair is reflected in characteristic defect patterns observed in empty-state STM images, which arise from the bright appearance of Ce(4+) ions next to the defect while the Ce(3+) remain dark. Both findings demonstrate that at least one excess electron localizes in a Ce ion that is not adjacent to the O vacancy.
authors.affiliation: Fritz-Haber-Institut der MPG, Berlin, Germany.
authors.forename: Jan-Frederik
authors.initials: JF
authors.lastname: Jerratsch
authors.forename: Xiang
authors.initials: X
authors.lastname: Shao
authors.forename: Niklas
authors.initials: N
authors.lastname: Nilius
authors.forename: Hans-Joachim
authors.initials: HJ
authors.lastname: Freund
authors.forename: Cristina
authors.initials: C
authors.lastname: Popa
authors.forename: M Veronica
authors.initials: MV
authors.lastname: Ganduglia-Pirovano
authors.forename: Asbjörn M
authors.initials: AM
authors.lastname: Burow
authors.forename: Joachim
authors.initials: J
authors.lastname: Sauer