title: Subsurface cation vacancy stabilization of the magnetite (001) surface.
abstract: Iron oxides play an increasingly prominent role in heterogeneous catalysis, hydrogen production, spintronics, and drug delivery. The surface or material interface can be performance-limiting in these applications, so it is vital to determine accurate atomic-scale structures for iron oxides and understand why they form. Using a combination of quantitative low-energy electron diffraction, scanning tunneling microscopy, and density functional theory calculations, we show that an ordered array of subsurface iron vacancies and interstitials underlies the well-known (√2 × √2)R45° reconstruction of Fe3O4(001). This hitherto unobserved stabilization mechanism occurs because the iron oxides prefer to redistribute cations in the lattice in response to oxidizing or reducing environments. Many other metal oxides also achieve stoichiometry variation in this way, so such surface structures are likely commonplace.
authors.affiliation: Institute of Applied Physics, Wiedner Hauptstrasse 8-10, Vienna University of Technology, 1040 Vienna, Austria.
authors.forename: R
authors.initials: R
authors.lastname: Bliem
authors.affiliation: Institute of Materials Chemistry, Getreidemarkt 9, Vienna University of Technology, 1060 Vienna, Austria.
authors.forename: E
authors.initials: E
authors.lastname: McDermott
authors.affiliation: Chair of Solid State Physics, University of Erlangen-Nürnberg, Staudtstrasse 7, 91058 Erlangen, Germany.
authors.forename: P
authors.initials: P
authors.lastname: Ferstl
authors.affiliation: Institute of Applied Physics, Wiedner Hauptstrasse 8-10, Vienna University of Technology, 1040 Vienna, Austria.
authors.forename: M
authors.initials: M
authors.lastname: Setvin
authors.affiliation: Institute of Applied Physics, Wiedner Hauptstrasse 8-10, Vienna University of Technology, 1040 Vienna, Austria.
authors.forename: O
authors.initials: O
authors.lastname: Gamba
authors.affiliation: Institute of Applied Physics, Wiedner Hauptstrasse 8-10, Vienna University of Technology, 1040 Vienna, Austria.
authors.forename: J
authors.initials: J
authors.lastname: Pavelec
authors.affiliation: Chair of Solid State Physics, University of Erlangen-Nürnberg, Staudtstrasse 7, 91058 Erlangen, Germany.
authors.forename: M A
authors.initials: MA
authors.lastname: Schneider
authors.affiliation: Institute of Applied Physics, Wiedner Hauptstrasse 8-10, Vienna University of Technology, 1040 Vienna, Austria.
authors.forename: M
authors.initials: M
authors.lastname: Schmid
authors.affiliation: Institute of Applied Physics, Wiedner Hauptstrasse 8-10, Vienna University of Technology, 1040 Vienna, Austria.
authors.forename: U
authors.initials: U
authors.lastname: Diebold
authors.affiliation: Institute of Materials Chemistry, Getreidemarkt 9, Vienna University of Technology, 1060 Vienna, Austria.
authors.forename: P
authors.initials: P
authors.lastname: Blaha
authors.affiliation: Chair of Solid State Physics, University of Erlangen-Nürnberg, Staudtstrasse 7, 91058 Erlangen, Germany.
authors.forename: L
authors.initials: L
authors.lastname: Hammer
authors.affiliation: Institute of Applied Physics, Wiedner Hauptstrasse 8-10, Vienna University of Technology, 1040 Vienna, Austria. parkinson@iap.tuwien.ac.at.
authors.forename: G S
authors.initials: GS
authors.lastname: Parkinson