Non-contact atomic force microscopy study of hydroxyl groups on the spinel MgAl2O4(100) surface

Research output: Contribution to journal/Conference contribution in journal/Contribution to newspaperJournal articleResearchpeer-review

  • F. Federici Canova, Tampere University of Technology
  • ,
  • A.S. Foster, Tampere University of Technology
  • ,
  • M.K. Rasmussen, Denmark
  • K. Meinander, Denmark
  • F. Besenbacher
  • Jeppe Vang Lauritsen
Atom-resolved non-contact atomic force microscopy (NC-AFM) studies of the magnesium aluminate (MgAl O ) surface have revealed that, contrary to expectations, the (100) surface is terminated by an aluminum and oxygen layer. Theoretical studies have suggested that hydrogen plays a strong role in stabilizing this surface through the formation of surface hydroxyl groups, but the previous studies did not discuss in depth the possible H configurations, the diffusion behaviour of hydrogen atoms and how the signature of adsorbed H is reflected in atom-resolved NC-AFM images. In this work, we combine first principles calculations with simulated and experimental NC-AFM images to investigate the role of hydrogen on the MgAl O (100) surface. By means of surface energy calculations based on density functional theory, we show that the presence of hydrogen adsorbed on the surface as hydroxyl groups is strongly predicted by surface stability considerations at all relevant partial pressures of H and O . We then address the question of how such adsorbed hydrogen atoms are reflected in simulated NC-AFM images for the most stable surface hydroxyl groups, and compare with experimental atom-resolved NC-AFM data. In the appendices we provide details of the methods used to simulate NC-AFM using first principles methods and a virtual AFM.
Original languageEnglish
JournalNanotechnology
Volume23
Issue32
ISSN0957-4484
DOIs
Publication statusPublished - 17 Aug 2012

See relations at Aarhus University Citationformats

ID: 48682870