Atomic, molecular and chemical physics LEED analysis
Shvets, I. V.; Berdunov, N.; Mariotto, G.; Murphy, S., Formation of the strain-induced electronic superstructure on the magnetite (111) surface, Europhysics Letters, 63, 6, 2003, 867-873
Europhysics Letters 63 6
We present direct experimental evidence of the formation of a superstructure on
the (111) surface of a magnetite, Fe3O4 single crystal. The superstructure, which has a periodicity
of 42A and three-fold symmetry, has been observed by means of STM and LEED. Under
the correct conditions of oxygen pressure and sample anneal temperature, the superstructure
is reproducibly formed throughout most of the sample surface. Clear atomic resolution within
the superstructure has been achieved. The characteristics of the superstructure, includingits
dependency on the tunnel bias voltage and its atomic-scale periodicity, suggest that it is an
electronic effect rather than a mosaic of several iron oxide phases. We explain the results in
terms of the formation of giant static polarons, although we notice that other types of electronlattice
instabilities such as charge density wave may offer possible explanations. Polarons with
dimensions of many interatomic distances in three-dimensional systems are unlikely to exist
but the situation for two- and one-dimensional cases is predicted to be different. We suggest
three possible scenarios of instability linkingthe electron band structure and lattice distortions
in magnetite: either resulting from reallocation of Fe2+ and Fe3+ valence states between
octahedral sites or, alternatively, from reallocation between octahedral and tetrahedral sites.
Please note: There is a known bug in some browsers that causes an
error when a user tries to view large pdf file within the browser window.
If you receive the message "The file is damaged and could not be
repaired", please try one of the solutions linked below based on the
browser you are using.
Items in TARA are protected by copyright, with all rights reserved, unless otherwise indicated.