Initial Fe3O4(100) Formation on Fe(100)
Artikel i vetenskaplig tidskrift, 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

Författare

Markus Soldemo

Kungliga Tekniska Högskolan (KTH)

Matthias Vandichel

Aalto-Yliopisto

Göteborgs universitet, Institutionen för Kemi

Henrik Gronbeck

Chalmers, Fysik, Kemisk fysik

Jonas Weissenrieder

Kungliga Tekniska Högskolan (KTH)

Journal of Physical Chemistry C

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

Vol. 123 26 16317-16325

Ämneskategorier

Oorganisk kemi

Materialkemi

DOI

10.1021/acs.jpcc.9b04625

Mer information

Senast uppdaterat

2019-10-18