Regensburg 2010 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 26: Poster Session

MM 26.38: Poster

Dienstag, 23. März 2010, 14:45–16:30, Poster C

Finite-Size effects in GaN nanoparticles studied by a novel dynamic-charge transfer potential — •Manuel Diehm, Peter Agoston, and Karsten Albe — Technische Universität Darmstadt, Institut für Materialwissenschaft, Petersenstr. 23, 64287 Darmstadt

Nanoparticles of compound semiconductors exhibit a number of peculiar properties, including phase transitions and unusual structural relaxations. Atomic scale modelling of such effects by quantum mechanical ab-initio calculations is, however, computationally too demanding, while classical potentials are limited to fixed charge models or computationally costly charge equilibration schemes. In this contribution, a novel dynamic charge-transfer bond-order potential (DCT-BOP) is applied, which opens the possibility to study larger ionic systems with variable charge states. The variability of the charges may carry great importance when modelling nanoparticles, since a reduction in the charge state of an ion can mitigate the impact of missing Coulomb interactions at surfaces or defects and change the energetics of relaxation. Here, we present calculations on Gallium Nitride nanoparticles using the DCT-BOP in comparison to a conventional bond-order potential and a pure Coulomb/Buckingham Potential. We examine the size dependence of charge states, relaxation energy gain and the interplay of surface and bulk contributions.