SKM 2023 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 19: Crystallization, Nucleation and Self-Assembly
CPP 19.9: Vortrag
Dienstag, 28. März 2023, 12:00–12:15, MER 02
Non-metallic quasicrystals minimize sphere packing energy — •Martin Dulle1, Vladislava Fokina1, Thomas Gruhn2, and Stephan Förster1 — 1Forschungszentrum Jülich, Jülich, Germany — 2Universität Bayreuth, Bayreuth, Germany
Quasicrystals are a peculiar state of order, which is fundamentally different from classical ordered crystalline states. Discovered in 1982 for metal alloys, they have in recent years also been reported for an increasing number of non-metallic materials.
Using MD-simulations we calculate the phase diagram of soft repulsive core/shell particles and find stability regions for seven different octagonal, decagonal, dodecagonal and icosahedral quasicrystals. We compare the structure and stability region of the dodecaganol phase with experiments on different polymer and nanoparticle systems and find quantitative agreement. We identify a new high density dodecagonal phase in a large number of reported non-metallic quasicrystalline systems including polymers, mesoporous silica, surfactants, BaTiO3, TaTe and MnCrNiSi. All remaining reported non-metallic quasicrystals can be related to the other simulated quasicrystal types.
We geometrically derive all respective tilings and show how in-plane quasicrystalline order is combined with axial periodic order via the realization of certain gyro-elongated bipyramids. This geometrical arrangement minimizes sphere packing energy for certain length scale ratios and particle densities, irrespective of the absolute length scale, the type of interactions and chemical constituents.