Regensburg 2019 – scientific programme

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DY: Fachverband Dynamik und Statistische Physik

DY 54: Poster: Complex, Fluids, Glasses, Granular

DY 54.1: Poster

Thursday, April 4, 2019, 15:00–18:00, Poster B2

A Phase Field Crystal Approach for Patchy Colloids — •Robert F. B. Weigel and Michael Schmiedeberg — Institut für Theoretische Physik, FAU Erlangen-Nürnberg, 91058 Erlangen, Germany

Patchy colloids are particles with discrete rotational symmetry and anisotropic interaction, thus preferring certain bond angles. Finding the complex equilibrium phases in systems with patchy colloids is challenging.

We propose and study a mean field model for patchy colloids that is motivated by the phase field crystal theory for systems with particles exhibiting 2-fold rotational symmetry as in liquid crystals for which a theory has been proposed in [1]. In such an approach the free energy F[ψ,U] is given as a functional of a real-valued density-like field ψ and a complex-valued orientation field U, which encodes the intensity and direction of the orientation. As usual in phase field crystal models, F is composed of a Landau-like power series in the fields along with an expansion with respect to the gradients as well as coupling terms respecting the rotational symmetry of the particles. Numerical minimization of F yields a rich phase diagram of complex structures. Our special interest is to find out how orderings with non-crystallographic symmetries, such as in quasicrystals, can be obtained.

[1] Achim et al., Phys. Rev. E 83, 061712 (2011)