Regensburg 2007 – scientific programme

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O: Fachverband Oberflächenphysik

O 44: Poster Session II (Semiconductors; Oxides and Insulators: Adsorption, Clean Surfaces, Epitaxy and Growth; Surface Chemical Reactions and Heterogeneous Catalysis; Surface or Interface Magnetism; Solid-Liquid Interfaces; Organic, Polymeric, Biomolecular Films; Particles and Clusters; Methods: Atomic and Electronic Structure; Time-resolved Spectroscopies)

O 44.28: Poster

Wednesday, March 28, 2007, 17:00–19:30, Poster C

DFT-Investigations of Coalescence Behaviour of Small Magic Si Clusters on Surfaces — •Wolfram Quester and Peter Nielaba — Fachbereich Physik, Universität Konstanz, 78457 Konstanz

Experimental results indicate that small magic Si clusters do not form islands of bulk Si on weakly interacting surfaces (HOPG). For Si₄ this was confirmed in earlier calculations [1]. This leads to the question if these clusters are suited as building blocks for new cluster materials.

These investigations were extended to Si₇. Potential energy curves of two approaching Si₇ clusters were calculated for different reaction channels using Density Functional Theory implemented in the CPMD code available at [2]. It could be shown that the cluster-cluster interaction is either repulsive or there are fusion barriers higher than room temperature.

Since the influence of the surface is important, the next step was to include the graphite surface in the simulations. Also the influence of defects was to be studied.

• [1] M. Grass, D. Fischer, M. Mathes, G. Ganteför and P. Nielaba, Appl. Phys. Lett., 81, 3810 (2002)
• [2] www.cpmd.org