Entropy and kinetics of point defects in two-dimensional dipolar crystals

Autor(en)

Wolfgang Lechner, David Polster, Georg Maret, Christoph Dellago, Peter Keim

Abstrakt

We study in experiment and with computer simulation the free energy and the kinetics of vacancy and interstitial defects in two-dimensional dipolar crystals. The defects appear in different local topologies, which we characterize by their point group symmetry; Cn is the n-fold cyclic group and D-n is the dihedral group, including reflections. The frequency of different local topologies is not determined by their almost degenerate energies but is dominated by entropy for symmetric configurations. The kinetics of the defects is fully reproduced by a master equation in a multistate Markov model. In this model, the system is described by the state of the defect and the time evolution is given by transitions occurring with particular rates. These transition rate constants are extracted from experiments and simulations using an optimization procedure. The good agreement between experiment, simulation, and master equation thus provides evidence for the accuracy of the model.

Organisation(en)

Institut für Lehrer*innenbildung, Computergestützte Physik und Physik der Weichen Materie

Externe Organisation(en)

Österreichische Akademie der Wissenschaften (ÖAW), Leopold-Franzens-Universität Innsbruck, Universität Konstanz

Journal

Physical Review E

Band

91

Anzahl der Seiten

9

ISSN

1539-3755

DOI

https://doi.org/10.1103/PhysRevE.91.032304

Publikationsdatum

03-2015

Peer-reviewed

Ja

ÖFOS 2012

103015 Kondensierte Materie, 103029 Statistische Physik

Schlagwörter

ASJC Scopus Sachgebiete

Condensed Matter Physics, Statistical and Nonlinear Physics, Statistics and Probability

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/898c6ed0-9d6e-406a-93b1-02f6428f2f4c