Dresden 2006 – scientific programme

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MM: Metall- und Materialphysik

MM 24: Quasicrystals

MM 24.4: Talk

Wednesday, March 29, 2006, 14:45–15:00, IFW D

Structure factor of the harmonic Fibonacci chain — •Steffen Sonntag, Michael Engel, Hansjörg Lipp, and Hans-Rainer Trebin — Universität Stuttgart, Institut für Theoretische und Angewandte Physik, 70550 Stuttgart

In quasicrystals peculiar dynamic modes, the phasons, are existing in addition to the usual phonons. However, experimentally little is known about their precise nature. In order to investigate the interplay between phasons and phonons on an elementary level we resort to various one-dimensional model systems and study them with a special molecular dynamics code. Our main observables of the dynamics are the coherent and the incoherent dynamical structure factor. In a first talk we present simulation results for harmonic chains, (i.e. chains without phason flips), especially the harmonic Fibonacci chain. The structure factor consists of one-phonon and multi-phonon branches arranged periodically or quasiperiodically and is resolved in great detail by our algorithm. Comparison is made to analytical calculations which can be performed for certain approximations. The examination of the harmonic Fibonacci chain is prerequisite for separating phonon and phason dynamics in a chain with flippable atoms.