Berlin 2015 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 58: Poster - Fluids

DY 58.8: Poster

Donnerstag, 19. März 2015, 16:00–18:00, Poster A

Excitation of defects in colloidal quasicrystals close to the melting transition — •Miriam Martinsons and Michael Schmiedeberg — Institut für Theoretische Physik 2: Weiche Materie, Heinrich-Heine Universität Düsseldorf, 40204 Düsseldorf, Germany

Quasicrystals are structures with long range order but no translational symmetry. They can have any rotational symmetry including those that are not allowed in periodic crystals. In quasicrystals there are phononic modes as well as additional hydrodynamic modes called phasons. Such phasons correspond to correlated rearrangements of the particles and arise as a consequence of the additional degrees of freedom that do not exist in periodic crystals.

We study how local and global excitations or defects develop in quasicrystals close to the melting transition. Local excitations termed phasonic flips only occur in quasiperiodic systems. Other defects, e.g. dislocations and disclinations, cause the melting of the quasicrystal as predicted by the KTHNY theory. We analyze the positional and bond-orientational correlation functions during the melting process. Our studies reveal the similarities and differences of the melting mechanism of quasicrystals as compared to the melting of periodic crystals.