Structure of the Ultrathin Aluminum Oxide Film on NiAl(110)
Georg Kresse,1*
Michael Schmid,2
Evelyn Napetschnig,2
Maxim Shishkin,1
Lukas Köhler,1
Peter Varga2
The well-ordered aluminum oxide film formed by oxidation of
the NiAl(110) surface is the most intensely studied metal surface
oxide, but its structure was previously unknown. We determined
the structure by extensive ab initio modeling and scanning tunneling
microscopy experiments. Because the topmost aluminum atoms are
pyramidally and tetrahedrally coordinated, the surface is different
from all Al
2O
3 bulk phases. The film is a wide-gap insulator,
although the overall stoichiometry of the film is not Al
2O
3 but Al
10O
13. We propose that the same building blocks can be
found on the surfaces of bulk oxides, such as the reduced corundum
(0001) surface.
2 Institut für Allgemeine Physik, Technische Universität Wien, A-1040 Wien, Austria.
* To whom correspondence should be addressed. E-mail: Georg.Kresse{at}univie.ac.at
