Regensburg 2002 – wissenschaftliches Programm

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O: Oberflächenphysik

O 9: Adsorption an Oberfl
ächen (I)

O 9.11: Vortrag

Montag, 11. März 2002, 17:45–18:00, H36

Surface Segregation of Ordered Alloys Studied by Low-Energy Ion Scattering - the Example CuAu — •Robert Beikler and Edmund Taglauer — Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, D-85748 Garching

Low-Energy Ion Scattering (LEIS) is a very suitable tool for probing selectively the topmost one, two or three layers of alloy crystal surfaces. An advanced procedure for the analysis of crystalline alloy surfaces by using experiments and simulations is exemplified with CuAu(100). This kind of analysis is not restricted to this case but with the necessary modifications an application to other crystalline materials is possible. The quantitative evaluation of the experimental LEIS-intensities is performed by comparison with numerical MARLOWE simulations [1, 2, 3].

The ordered alloy CuAu(100) shows nearly bulk truncation with Au termination below the critical temperature T₀ of chemical ordering and exhibits strong first layer Au segregation above T₀. The results indicate the appearance of an oscillatory segregation profile and are in good agreement with theoretical predictions from Tersoff [4].

[1] R. Beikler, E. Taglauer, Nucl. Inst. Phys. Res. B 161-163 (2000) 390-395.

[2] R. Beikler, E. Taglauer, accepted by Nucl. Inst. Phys. Res. B (2001).

[3] M.T. Robinson, I.M. Torrens, Phys. Rev. B9 (1974) 5008.