Berlin 2015 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 70: Complex Fluids and Soft Matter - Part III (joint session DY, CPP, BP)
CPP 70.2: Talk
Thursday, March 19, 2015, 15:30–15:45, BH-N 334
Quasicrystalline Order and a “Crystal-Liquid" State in a Soft-Core Fluid — •Andrew Archer1, Alastair Rucklidge2, and Edgar Knobloch3 — 1Department of Mathematical Sciences, Loughborough University, Loughborough, LE11 3TU, UK — 2Department of Applied Mathematics, University of Leeds, Leeds LS2 9JT, UK — 3Department of Physics, University of California at Berkeley, Berkeley, CA 94720, USA
Results will be presented for a two-dimensional system of soft particles interacting via a two-length-scale potential that may be considered to be a simple model for the effective interaction between dendrimers and other such polymeric macromolecules in solution. Density functional theory and Brownian dynamics simulations reveal the system has a fluid phase and two crystalline phases with different lattice spacing. Of these the larger lattice spacing phase can form an exotic periodic state with a sizeable fraction of highly mobile particles: a “crystal liquid”. Near the transition between this phase and the smaller lattice spacing phase, quasicrystalline (QC) structures may be created by a competition between linear instability at one scale and nonlinear selection of the other. This dynamic mechanism for forming QCs is qualitatively different from mechanisms observed previously. The system first forms a small length scale crystal. Only when this phase is almost fully formed (i.e., the dynamics is far into the nonlinear regime) does the longer length scale start to appear, leading to the formation of QCs [A.J. Archer, A.M. Rucklidge, and E. Knobloch, Phys. Rev. Lett. 111, 165501 (2013)].