Dresden 2003 – wissenschaftliches Programm
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O: Oberflächenphysik
O 22: Epitaxie und Wachstum I
O 22.7: Vortrag
Dienstag, 25. März 2003, 16:30–16:45, FOE/ORG
X-ray structure analysis of the 2D dislocation network of Fe on W(110) — •R. Popescu1, H. L. Meyerheim1, D. Sander1, P. Steadman2, O. Robach2, S. Ferrer2, and J. Kirschner1 — 1Max-Planck Institut f. Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany — 2ESRF, BP 220, F-38043 Grenoble, France
The geometric structure of the 2-dimensional dislocation network of Fe on W(110) [1] was investigated using surface x-ray diffraction at the ESRF (Grenoble, France). After deposition of 13 monolayers (ML) Fe the intensity distribution of in total 14 satellite rods were collected. The network superstructure with lateral lattice constants of 35.84 Å and 50.76 Å along [001] und [-110], respectively is incommensurate with the W(110) surface, which nearly corresponds to a 37/34 coincidence between the Fe- and the W-atoms. The unit cell of the average Fe-structure is monoclinic with lattice parameters of a=b=2.887(2) Å, c= 2.901(5) Å, and the monoclinic angle γ=89.4 ∘ (bulk bcc Fe: a=b=c=2.866 Å, γ=90 ∘). From the intensity analysis maximum lateral and vertical modulation amplitudes of 0.7 and 1.2 Å are derived, which decrease with distance from the Fe/W(110) interface. The results are discussed in the context with STM data [2] and theory [3].
[1] U. Gradmann und G. Waller, Surf. Sci. 116, 539 (1982) [2] D. Sander et al. Surf. Sci. 402-404, 351 (1998) [3] J. H. van der Merve, J. Appl. Phys. 34, 123 (1963)