Dresden 2006 – wissenschaftliches Programm

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O: Oberflächenphysik

O 14: Poster session I (Adsorption, Epitaxy and growth, Phase transitions, Surface reactions, Organic films, Electronic structure, Methods) (sponsored by Omicron Nanotechnology GmbH)

O 14.32: Poster

Montag, 27. März 2006, 18:00–21:00, P2

Structure und Growth of Fe Films on the Ir(100)-(1×1) surface — •Verena Martin, Chiara Giovanardi, Wolfgang Meyer, Lutz Hammer, and Klaus Heinz — FAU Erlangen-Nürnberg, Lehrstuhl für Festkörperphysik, Staudtstr.7, D-91058 Erlangen

The growth of iron on the metastable (1×1) phase of Ir(100) in the coverage regime of 1 - 9 monolayers (ML) was investigated by STM and quantitative LEED. The films were deposited at low sample temperature (100 K) and subsequently annealed to about 420 K in order to improve the film quality. LEED intensity spectra probing the local film structure prove that this annealing procedure has no influence on the structure and stoichiometry of the films. STM shows that rather flat films result in the whole thickness regime. Clear (1×1) LEED patterns without any satellite features indicate pseudomorphic growth despite the large lattice misfit of 5.3% between Ir and bcc Fe. LEED structure determinations performed for films of various thicknesses reveal a tetragonally distorted bcc film structure with a 14% vertical expansion of deeper layer spacings. In contrast and unusual for metal surfaces, the outermost two layer distances are even further expanded, a feature also found for similarly distorted Fe films on Rh(100) [1]. Low temperature hydrogen adsorption induces on the Fe films a surface reconstruction.

[1] A.M. Begley, S.K. Kim, F. Jona, P.M. Marcus, Phys. Rev. B 48 (1993) 1786