Dresden 2009 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 40: Quasicrystals I

MM 40.5: Vortrag

Donnerstag, 26. März 2009, 11:15–11:30, IFW D

Structures of Colloidal Quasicrystals — •Johannes Roth — ITAP, Universiät Stuttgart, Germany

Quasicrystals and archimedean-like tilings formed by strips of squares and triangles have recently been observed in experiments of colloidal particles on laser-generated quasicrystalline substrate potentials (Nature 454, 501 (2008)). Restricted square-triangle tilings are also present in a model of binary dipolar colloids. We will present several classes of restricted square-triangle tilings and will study their properties by Monte-Carlo simulations.

In a second part we will discuss the properties of quasicrystalline laser potentials with respect to the number of beams. We find that there are significant differences between the five-fold case generated by linearly polarized light on the one hand and other polarizations or seven-fold symmetry on the other hand. In the first case the trapping sites form a structure close to a quasiperiodic tiling while in the second case there are low lying saddle points and far fewer deep minima.