Solidification in soft-core fluids: disordered solids from fast solidification fronts
arXiv:1407.7099 · doi:10.1103/PhysRevE.90.042404
Abstract
Using dynamical density functional theory we calculate the speed of solidification fronts advancing into a quenched two-dimensional model fluid of soft-core particles. We find that solidification fronts can advance via two different mechanisms, depending on the depth of the quench. For shallow quenches, the front propagation is via a nonlinear mechanism. For deep quenches, front propagation is governed by a linear mechanism and in this regime we are able to determine the front speed via a marginal stability analysis. We find that the density modulations generated behind the advancing front have a characteristic scale that differs from the wavelength of the density modulation in thermodynamic equilibrium, i.e., the spacing between the crystal planes in an equilibrium crystal. This leads to the subsequent development of disorder in the solids that are formed. For the one-component fluid, the particles are able to rearrange to form a well-ordered crystal, with few defects. However, solidification fronts in a binary mixture exhibiting crystalline phases with square and hexagonal ordering generate solids that are unable to rearrange after the passage of the solidification front and a significant amount of disorder remains in the system.
18 pages, 14 figs
References in corpus (12)
- Phase-field-crystal models for condensed matter dynamics on atomic length and diffusive time scales: an overview
- Dynamical density functional theory for interacting Brownian particles: stochastic or deterministic?
- Derivation of the phase field crystal model for colloidal solidification
- Why do ultrasoft repulsive particles cluster and crystallize? Analytical results from density functional theory
- Phase-field crystal modeling of equilibrium bcc-liquid interfaces
- Morphology changes in the evolution of liquid two-layer films
- Diffusion and Relaxation Dynamics in Cluster Crystals
- Solidification fronts in supercooled liquids: how rapid fronts can lead to disordered glassy solids
- Glass Transition of Hard Sphere Systems: Molecular Dynamics and Density Functional Theory
- Demixing cascades in cluster crystals
- Crystallization: Colloidal suspense
- [N]pT ensemble and finite-size scaling study of the GEM-4 critical isostructural transition