[SY-I12] Symposium I-12

[SY-I12] Growth and characterization of two-dimensional poly(quasi)crystals

^○Petri Hirvonen¹, Gabriel Martine La Boissonière², Zheyong Fan¹, Cristian Achim³, Nikolas Provatas⁴, Ken R. Elder⁵, Tapio Ala-Nissila^1,6 (1.Dept. of Applied Physics, Aalto Univ., Finland, 2.Dept. of Mathematics and Statistics, McGill Univ., Canada, 3.Dept. of Chemical Engineering, Univ. of Concepción, Chile, 4.Dept. of Physics, McGill Univ., Canada, 5.Dept. of Physics, Oakland Univ., United States of America)

We use a simple two-mode phase field crystal (PFC) model to simulate grain growth in realistic two-dimensional model systems of square and hexagonal, as well as of 10- and 12-fold symmetric quasicrystal lattice symmetries. Modeling the evolution of poly(quasi)crystals had remained a challenge until the arrival of PFC, giving access to long diffusive time scales. We characterize the model systems using a powerful new method for segmenting and analyzing grain structures. This method generalizes effortlessly to all lattice types of even-fold rotational symmetry. To our knowledge, our characterization method is the first of its kind so far for quasicrystals.

The grain structure segmentations produced by the characterization method are found to agree very well with the corresponding human-made segmentations. We observe power-law scaling of the average grain size as a function of the simulation time, and log-normal grain size distributions for all lattice types considered. Similarly, irrespective of the lattice type, grain misorientation distributions appear remarkably flat, indicative of little correlation in the lattice orientations between neighboring grains. Average number of neighboring grains is between 5 and 6. We are currently working on improving our statistics to cut down the error margins and to verify or to refute the universality of these, and of further related, distributions.