Berlin 2015 – wissenschaftliches Programm
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DY: Fachverband Dynamik und Statistische Physik
DY 13: Crystallization, Nucleation and Self Assembly II (joint session CPP/ DY)
DY 13.3: Vortrag
Montag, 16. März 2015, 16:15–16:30, PC 203
Solidification fronts in supercooled liquids: how rapid fronts can lead to disordered glassy solids — •Andrew Archer1, Morgan Walters1, Uwe Thiele2, and Edgar Knobloch3 — 1Department of Mathematical Sciences, Loughborough University, Loughborough, LE11 3TU, UK — 2Westfälische Wilhelms-Universität Münster, Institut für Theorestische Physik, Wilhelm-Klemm-Str. 9, 48149 Münster, Deutschland — 3Department of Physics, University of California at Berkeley, Berkeley, CA 94720, USA
We determine the speed of a crystallization/solidification front as it advances into the uniform liquid phase after it has been quenched into the crystalline region of the phase diagram, for systems of soft particles. We calculate the front speed by assuming the system can be treated using dynamical density functional theory (DDFT). There are two mechanisms by which the front can advance, depending on whether the liquid state is linearly stable or not. When linearly unstable, the front speed can be calculated by applying a marginal stability criterion. As the solidification front advances, the density profile behind the advancing front develops density modulations, whose wavelength λ is a dynamically chosen quantity. For shallow quenches, λ is close to that of the crystalline phase and so well-ordered crystalline states are formed. However, when the system is deeply quenched, λ can be quite different from that of the crystal, so the solidification front naturally generates disorder in the system. Significant rearrangement and aging must subsequently occur for the system to form the regular well-ordered crystal that corresponds to the free energy minimum.