Dresden 2011 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 31: Postersitzung II

MM 31.2: Poster

Mittwoch, 16. März 2011, 17:15–18:45, P5

Refined model of phason flips in quasicrystals using kinetic Monte Carlo simulations — •Hansjörg Lipp and Hans-Rainer Trebin — Institut für Theoretische und Angewandte Physik, Universität Stuttgart, Germany

HRTEM observations of decagonal Quasicrystals by Edagawa et al. [1] show that phason flips can be observed directly as spots which vanish or appear erratically. The spots can be interpreted as clusters of atoms, which move coherently. Compared to the time scale of atomic jumps (picoseconds), this process is surprisingly slow, flips occur in periods of seconds or even minutes.

We study this phenomenon using several statistical model systems, e.g. based on a structure model for d-Al-Cu-Co suggested by Zeger et al. [2], where rings of ten atoms can perform flips by collective motion of atoms inside decagonal double layers. Using kinetic Monte Carlo simulations [3], we investigate how flip frequencies depend on the number of decagonal layers and on the variations of the local energy landscape.

[1] K. Edagawa et al., Phys. Rev. Lett. 85, 1674 (2000)

[2] G. Zeger and H.-R. Trebin, Phys. Rev. B 54, R720 (1996)

[3] A. B. Bortz et al., J. Comput. Phys. 17, 10 (1975)