Regensburg 2004 – wissenschaftliches Programm

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M: Metallphysik

M 29: Quasikristalle I

M 29.1: Vortrag

Donnerstag, 11. März 2004, 14:45–15:00, H16

Force-Matched EAM Potentials for Decagonal AlNiCo — •Peter Brommer and Franz Gähler — Universität Stuttgart, Institut für Theoretische und Angewandte Physik, 70550 Stuttgart

Aluminum mobility in decagonal AlNiCo displays interesting peculiarities. At 80 % of the melting temperature some aluminum atoms can move around the quasicrystal, while others remain firmly locked in place. Molecular dynamics simulations can offer insights into the dynamics of this system. Ideally one would use ab-initio methods to evaluate the many-body quantum mechanical equations, but those methods are limited to a few hundred atoms. On the other hand, the application of effective potentials allows much larger systems. Then the problem is to find suitable potentials, which are not available for complex systems like quasicrystals. Force Matching is a way to derive effective potentials from quantum-mechanical input data, thereby combining the advantages of the two methods. The idea is that a potential that reproduces the forces correctly also yields the correct dynamics. The application of this method to the decagonal AlNiCo quasicrystalline phase is described and test simulations with the derived potentials will be presented.