Berlin 2005 – wissenschaftliches Programm

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O: Oberflächenphysik

O 15: Postersitzung (Adsorption an Oberfl
ächen, Epitaxie und Wachstum, Organische Dünnschichten, Oxide und Isolatoren, Rastersondentechniken, Zeitaufgelöste Spektroskopie, Methoden)

O 15.28: Poster

Freitag, 4. März 2005, 17:00–20:00, Poster TU D

Growth of ultra-thin Fe films on Cu(111) — •Werner Rupp, Albert Biedermann, Michael Schmid, and Peter Varga — Institut für allgemeine Physik, Technische Universität Wien

Using scanning tunneling microscopy (STM), scanning tunnelling spectroscopy (STS) and low-energy electron diffraction (LEED) we have characterized ultra-thin films of Fe on Cu(111). The films were grown by thermal deposition (TD) at room temperature (RT). Whereas bulk Fe is normally bcc (α-Fe) at temperatures below 1186 K, fcc Fe (γ-Fe) can be stabilized in ultra thin films on fcc substrates. Analysing these TD-films, we find a pseudomorphic growth at low coverages [1]. With atomically resolved STM images we show the initial formation of strained bcc domains at low coverages (3ML) on flat Fe islands. This strain decreases with the thickness of the film. The bcc domains have Kurdjumov-Sachs orientation in agreement with LEED [2]. With STS measurements we show that the Cu covers the Fe islands decorating the step edges already during the deposition process. Correlated with this Cu coverage is the formation of 1ML high vacancy islands near the step edges of the substrate [3].

[1] J.Shen et al, Phys. Rev. B 56, 11134 [2] P. Ohresser et al, Phys. Rev. B. 59, 3696 [3] A. Brodde et al, Phys. Rev. B 47, 6609