Regensburg 2013 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 8: Topical Session: Quasicrystals & Complex Metallic Alloys II
MM 8.3: Topical Talk
Montag, 11. März 2013, 12:15–12:45, H25
Self-assembly and packing of polyhedra into complex crystal structures — •Michael Engel1, Pablo F. Damasceno1, Amir Haji-Akbari2, and Sharon C. Glotzer1 — 1Chemical Engineering, University of Michigan, USA — 2Chemical and Biological Engineering, Princeton University, USA
Isolating the role of building block shape for self-assembly and packing provides insight into the ordering of molecules and the crystallization of colloids, nanoparticles, proteins, and viruses. We investigated a large group of polyhedra whose phase behavior arises solely from their anisotropic shape by exploiting entropic driving forces. Our results demonstrate a remarkably high propensity for thermodynamic self-assembly and structural diversity [1]. In particular, I will discuss the formation and geometric stabilization of a dodecagonal quasicrystal with tetrahedra [2] as well as the appearance of topologically close-packed phases. All of the crystal structures we observe have analogues in the elements and can be understood by relating shape to atomic interactions. It turns out that the structural complexity is particularly high, when entropy and geometric constraints compete with locally dense configurations.
[1] P.F. Damasceno et al. Science 337, 453 (2012)
[2] A. Haji-Akbari et al. Nature 462, 773 (2009)