Prof. Primoz Ziherl: Mosaic two-lengthscale quasicrystals
Povzetek:
Mosaic two-lengthscale quasicrystals
Prof. Primoz Ziherl, Faculty of Mathematics and Physics, University of Ljubljana and Jozef Stefan Institute, Ljubljana
Over the past decade,quasicrystalline order has been observed in many soft-matter systems: in dendritic micelles, in star and tetra block terpolymer melts and in diblock copolymer and surfactant micelles. The formation of quasicrystal from such a broad range of ‘soft' macromolecular micelles suggests that they assemble by a generic mechanism rather than being dependent on the specific chemistry of each system. Indeed, micellar softness has been postulated and shown to lead to quasicrystalline order. We theoretically explore this link by studying two-dimensional hard disks decorated with steplike square-shoulder repulsion that mimics, for example, the soft alkyl shell around the aromatic core in dendritic micelles.We find a family of quasicrystals with 10-, 12-, 18- and 24-fold bond orientational order which originate from mosaics of equilateral and isosceles triangles formed by particles arranged core-to-core and shoulder-to-shoulder. The pair interaction responsible for these phases highlights the role of local packing geometry in generating quasicrystallinity in soft matter, complementing the principles that lead to quasicrystal formation in hard tetrahedra. Based on simple interparticle potentials, quasicrystalline mosaics may well find use in diverse applications ranging from improved image reproduction to advanced photonics materials*.
T. Dotera, T. Oshiro, and P. Ziherl, Nature 506, 208 (2014).
