Einladung zum Promotionsvortrag von Frau Miriam Martinsons:
„Phasonic Degrees of Freedom in Quasicrystals“
Quasicrystals are remarkable ordered structures without periodic translational symmetry. They can possess any discrete rotational symmetry including those that must not be present in periodic crystals. An important characteristic of quasicrystals is the existence of additional degrees of freedom whose excitations lead to rearrangements of particles. Such rearrangements are called phasonic flips.
The aim of this talk is to contribute to the understanding of the order and properties of quasicrystals. For this purpose we employ computational simulations of two-dimensional colloidal model systems where mesoscopic particles are suspended in a liquid. Significant new insights into the structural and dynamical complexity of quasicrystals are gained. We illustrate how the growth of quasicrystals is affected by thermodynamic parameters and phasonic flips. Especially the growth of nearly defect-free quasicrystals is presented. In addition, we focus on the dynamics of quasicrystals. The stability of quasicrystals against phasonic perturbations is investigated. Particles are identified which easily perform phasonic flips,
while other ones are rather stable. Our work provides significant progress in theory and simulations of quasicrystals and our results obtained from colloidal model systems are also relevant for other fields in physics, chemistry and material science. We expect that our work motivates further theoretical and experimental research on quasicrystals. (Vortrag auf Deutsch)
Dem Vortrag schließt sich eine Diskussion von 15 Minuten an. Vortrag und Diskussion sind öffentlich. Diesen Verfahrensteilen folgt ein nicht öffentliches Rigorosum von 45 Minuten.