Initial Fe3O4(100) Formation on Fe(100)
Journal article, 2019

The initial oxidation of Fe(100) at 400 degrees C has been studied by X-ray photoelectron spectroscopy (XPS), scanning tunneling microscopy (STM), and low-energy electron diffraction, in combination with density functional theory calculations. The first observed well-ordered surface oxide is formed at a coverage of similar to 3 oxygen atoms per unreconstructed surface Fe(100) atom. STM shows that this surface oxide is terminated by straight atomic rows exhibiting a p(2 X 1) periodicity. However, already for oxide films with a coverage of similar to 4 oxygen atoms (corresponding to one Fe3O4 unit cell thickness), wiggly atomic rows appear similar to the c(2 X 2) reconstructed Fe3O4 (100)-surface with the Fe3O4 unit vectors rotated 45 degrees to Fe(100). The wiggly rows are a consequence of subsurface cation iron vacancies, which previously have been observed for bulk surfaces. The formation of subsurface vacancies is supported by the XPS O is signature, which is modeled by considering the core-level shifts for all oxygen atoms in the film. Throughout the oxidation series, the microscopy results reveal a layer-by-layer (Frank-van der Merwe) growth.

Oxide films

Electrons

Density functional theory

magnetite

electron diffraction

X ray photoelectron spectroscopy

iron oxides

Scanning tunneling microscopy

Author

Markus Soldemo

Royal Institute of Technology (KTH)

Matthias Vandichel

Aalto University

University of Gothenburg, Department of Chemistry

Henrik Gronbeck

Chalmers, Physics, Chemical Physics

Jonas Weissenrieder

Royal Institute of Technology (KTH)

Journal of Physical Chemistry C

1932-7447 (ISSN) 1932-7455 (eISSN)

Vol. 123 26 16317-16325

Subject Categories

Inorganic Chemistry

Materials Chemistry

DOI

10.1021/acs.jpcc.9b04625

More information

Latest update

10/18/2019