Regensburg 2007 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 4: Liquid and amorphous materials II

MM 4.5: Talk

Monday, March 26, 2007, 12:45–13:00, H4

Phason flips and solitons in the dynamic Fibonacci chain — •Hansjörg Lipp, Steffen Sonntag, Michael Engel, and Hans-Rainer Trebin — Universität Stuttgart, Institut für Theoretische und Angewandte Physik, 70550 Stuttgart

Quasicrystals possess the phason degree of freedom which manifests itself in correlated atomic flip motions. To get insight into the microscopic dynamics of the flips, we studied one dimensional model systems: periodic and quasiperiodic anharmonic chains, in particular the quasiperiodic Fibonacci chain.

Here we present approximate analytic solutions of the equations of motion in such systems as well as results from molecular dynamics simulations. The chains show localized modes interacting with phonons. There are both breathers and kink solitons. Propagating solitons appear in two forms: The low energy form resembles standard solitons in anharmonic chains; the high energy form contains propagating flips. We discuss their stability and their contribution to energy transport.