Berlin 2012 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 2: Statistical Physics (General)

DY 2.2: Vortrag

Montag, 26. März 2012, 10:00–10:15, MA 004

Kinetics of Nucleation on Surfaces in the Ising model — •Fabian Schmitz, Peter Virnau, and Kurt Binder — Institut für Physik, Johannes Gutenberg-Universität Mainz - Staudingerweg 7, D-55099 Mainz, Germany

We consider homogeneous and heterogeneous nucleation in the 3d Ising model, and compare information gained from nucleation dynamics to free energy computations in the context of classical nucleation theory. To define ”physical clusters”, the Swendsen-Wang algorithm is applied. We force the system into a metastable state from which it escapes into a stable state via nucleation. In the heterogeneous case, two flat walls with surface fields are introduced on which nuclei grow with some contact angle depending on the surface fields. To extract the critical cluster size, at which clusters decay or grow with equal probability, we measure the average growth rate R(l) of nuclei with size l by monitoring the growth and decay of individual clusters over time for varying bulk and surface magnetic fields. Critical cluster sizes obtained from this method are comparable yet slightly larger than predicted from classical nucleation theory in both homogeneous and heterogeneous nucleation scenarios. The time dependence of the cluster distributions are also in agreement with previous predictions.