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O: Fachverband Oberflächenphysik

O 33: Symposium: Frontiers of Surface Sensitive Electron Microscopy I (Invited Speakers: James Hannon, Raoul van Gastel, Thomas Schmidt)

O 33.2: Hauptvortrag (ohne Erstattung)

Dienstag, 26. Februar 2008, 14:15–14:45, MA 005

The role of long-range interactions in determining surface morphologies: a combined LEEM/SXRD study — •Raoul van Gastel — MESA+ Institute for Nanotechnology, University of Twente, Enschede, The Netherlands

LEEM has been used to study long-ranged elastic interactions that occur in metal heteroepitaxy. The elastic interactions are used to achieve shaping and sizing of nanostructures. Pb/Cu(111) is first used as an example to illustrate how LEEM is applied to quantify the thermodynamic parameters that are driving the self-assembly of two phases, a surface alloy phase and an overlayer phase. We show how those parameters can be manipulated to induce size and shape changes of individual domains.

For the similar Bi/Cu(111) system we have combined surface X-ray diffraction (SXRD) and LEEM to investigate the atomic structure and pattern formation. We investigate the structure of the different surface phases and pinpoint the origin of the morphological changes to the atomic structure of the different phases. The pattern formation and the dramatic changes that occur during the transitions are analyzed and the thermodynamic parameters that control the rich phase behavior in this system are quantified. Finally, a brief illustration is given of how electrostatic interactions can lead to similar effects in the self-assembly of organic molecules on metal substrates.