Initial Fe3O4(100) Formation on Fe(100)

Research output: Contribution to journalArticleScientificpeer-review

Researchers

  • Markus Soldemo
  • Matthias Vandichel
  • Henrik Grönbeck
  • Jonas Weissenrieder

Research units

  • KTH Royal Institute of Technology
  • Chalmers University of Technology

Abstract

The initial oxidation of Fe(100) at 400 °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 ∼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 × 1) periodicity. However, already for oxide films with a coverage of ∼4 oxygen atoms (corresponding to one Fe3O4 unit cell thickness), wiggly atomic rows appear similar to the c(2 × 2) reconstructed Fe3O4(100)-surface with the Fe3O4 unit vectors rotated 45° 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 1s 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.

Details

Original languageEnglish
Pages (from-to)16317-16325
Number of pages9
JournalJournal of Physical Chemistry C
Volume123
Issue number26
Publication statusPublished - 12 Jun 2019
MoE publication typeA1 Journal article-refereed

ID: 36258618