Room temperature study of a strain-induced electronic superstructure on a magnetite (111) surface
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2004Citation:
Berdunov, N.; Murphy, S.; Mariotto, G.; Shvets, I. V., Room temperature study of a strain-induced electronic superstructure on a magnetite (111) surface, Physical Review B (Condensed Matter and Materials Physics), 70, 8, 2004, 85404Download Item:
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Abstract:
A magnetite sFe3O4d single-crystal (111) surface has been studied at various oxygen-iron surface stoichiometries.
The stoichiometry was modified by controlling the in situ sample anneal conditions. We have found
the conditions that lead to the formation of an oxygen-rich surface that forms a quasihexagonal superstructure
with a 42 ? periodicity. The superstructure is highly regular and was observed by both low-energy election
diffraction and scanning tunneling microscopy. The superstructure consists of three regions, two of which have
identical atomic scale structures with a periodicity of 2.8 ?, and a third having a periodicity that is about 10%
larger s3.1 ?d. The subtle difference in the atomic periodicities between the three areas results from the
modulation of intrinsic strain developed along the surface. The superstructure results from electronic effects
rather than being a mosaic of different iron oxide terminations. The onset of the superstructure is sensitive to
the surface stoichiometry. From our results we could estimate the critical density of defects leading to the
disappearance of the superstructure. We have modeled the experimental results and calculated the electron
density using density functional theory calculations. The model clearly shows the development of strain along
the surface.
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Science Foundation Ireland (SFI)
Author's Homepage:
http://people.tcd.ie/ivchvetshttp://people.tcd.ie/mariotl
http://people.tcd.ie/shmurphy
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Physical Review B (Condensed Matter and Materials Physics)70
8
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