Dresden 2017 – scientific programme

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DY: Fachverband Dynamik und Statistische Physik

DY 47: Complex Fluids and Soft Matter I (joint session DY/CPP)

DY 47.3: Talk

Thursday, March 23, 2017, 15:30–15:45, ZEU 160

Reconstruction of phason modes in colloidal quasicrystals — •Johannes Hielscher, Miriam Martinsons, Michael Schmiedeberg, and Sebastian C. Kapfer — FAU Erlangen-Nürnberg, Institut für Theoretische Physik

In colloidal quasicrystals, the idealised positions of the particles can be expressed in higher-dimensional space, accounting for the degrees of freedom of displacements within (phonons), and perpendicular (phasons) to the physical space. Phasonic displacements manifest in “flips”, i. e. characteristic particle jumps. Our model systems are two-dimensional intrinsic quasicrystals of decagonal symmetry, which are stabilised by a next-neighbour double-minimum pair potential. Brownian Dynamics and Monte Carlo simulations are conducted to let flip patterns develop at finite temperatures.

We present an method to analyse the flip pattern in a monocrystalline, dislocation-free quasicrystal by decomposition into long-wavelength harmonic phason modes [1]. Thermal flips are only partially accounted for by this approach. We discuss the break-down of the supposed phason-phonon coupling on the atomic scale, in the context of fundamental limitations of extended, collective phasonic distortions in soft quasicrystals with short-range interactions.

[1] J. Hielscher, M. Martinsons, M. Schmiedeberg & S. C. Kapfer: Detection of phonon and phason modes in intrinsic colloidal quasicrystals by reconstructing their structure in hyperspace. Submitted to J. Phys.: Cond. Matt.