Regensburg 2019 – scientific programme

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DY: Fachverband Dynamik und Statistische Physik

DY 32: Complex Fluids and Soft Matter (joint session DY/CPP)

DY 32.12: Talk

Wednesday, April 3, 2019, 18:15–18:30, H3

Crystallization of spheres with static and dynamic size dispersity — •Praveen Kumar Bommineni, Nydia Roxana Varela Rosales, Marco Klement, and Michael Engel — Institute for Multiscale Simulation, Friedrich-Alexander University Erlangen-Nürnberg, Nägelsbachstrasse 49b, 91052 Erlangen, Germany

Colloids are rarely uniform but follow a distribution of sizes, shapes, and charges. This dispersity can be inherent (static) or develop and change over time (dynamic). Despite a long history of research, the conditions under which non-uniform particles crystallize and which crystal forms is still not well understood. Here, we demonstrate that hard spheres with Gaussian radius distribution and dispersity up to 19% always crystallize if compressed slow enough, and they do so in surprisingly complex ways [1]. This result is obtained by accelerating event-driven simulations with particle swap moves for static dispersity and particle resize moves for dynamic dispersity. Above 6% dispersity, AB₂ Laves, AB₁₃, and a region of complex Frank-Kasper phases are found. The Frank-Kasper region includes a quasicrystal approximant with Pearson symbol oS276. Our findings are relevant for ordering phenomena in soft matter and alloys.

[1] P.K. Bommineni et al., arXiv:1811.00061.