Dresden 2003 – wissenschaftliches Programm
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O: Oberflächenphysik
O 39: Oxide und Isolatoren II
O 39.2: Vortrag
Freitag, 28. März 2003, 11:30–11:45, FOE/ORG
The surface termination of magnetite Fe3O4(001) — •Rossitza Pentcheva1,2, Frank Wendler2, Nathalie Jedrecy3, Wolfgang Moritz2, and Matthias Scheffler1 — 1Fritz-Haber-Institut der MPG, Berlin — 2Department for Earth and Environmental Sciences, LMU München — 3Lab. Mineralogie-Cristallographie, Université Paris 6 et 7
Magnetite is not only of substantial geological importance but also a promising material for the development of spintronic devices due to its half-metallic behavior. The (001)-surface of Fe3O4 exhibits a (√2× √2)R45∘ reconstruction which has not been unambiguously resolved to date. We performed density-functional-theory calculations with the FP-LAPW method within the generalized gradient correction (GGA) to study the structural and energetic properties of a variety of surface models proposed in the literature, e.g. an A termination with 0.5 ML tetragonal Fe or a B termination with oxygen vacancies. The results are compared to a recently completed x-ray diffraction analysis performed on a natural sample which favors the 0.5 ML A termination. Both the experimental and theoretical results reveal strong relaxations in the top layers extending over several layers.