Two-step nucleation in a binary mixture of Patchy Particles

Abstract

Nucleation in systems with a metastable liquid-gas critical point is the prototypical example of a two-step nucleation process, in which the appearance of the critical nucleus is preceded by the formation of a liquid-like density fluctuation. So far, the majority of studies on colloidal and protein crystallization have focused on one-component systems, and we are lacking a clear description of two-step nucleation processes in multicomponent systems, where critical fluctuations involve coupled density and concentrations inhomogeneities. Here, we examine the nucleation process of a binary mixture of patchy particles designed to nucleate into a diamond lattice. By combining Gibbs-ensemble simulations and direct nucleation simulations over a wide range of thermodynamic conditions, we are able to pin down the role of the liquid-gas metastable phase diagram on the nucleation process. In particular, we show that the strongest enhancement of crystallization occurs at an azeotropic point with the same stoichiometric composition of the crystal.

9 pages, 7 figures

References in corpus (13)

• Accurate determination of crystal structures based on averaged local bond order parameters
• Crystal Nucleation in Liquids: Open Questions and Future Challenges in Molecular Dynamics Simulations
• Phase diagram of patchy colloids: towards empty liquids
• How crystals form: A theory of nucleation pathways
• Nucleation in aqueous NaCl solutions shifts from 1-step to 2-step mechanism on crossing the spinodal
• Inverse Design for Self Assembly via On-the-Fly Optimization
• Non-classical pathways of crystallization in colloidal systems
• The physics of Empty Liquids: from Patchy particles to Water
• Designing patchy interactions to self-assemble arbitrary structures
• Inverse Statistical Mechanics: Probing the Limitations of Isotropic Pair Potentials to Produce Ground-State Structural Extremes
• Can Ordered Precursors Promote the Nucleation of Solid Solutions?
• Programming patchy particles to form complex periodic structures
• Empty liquid state and re-entrant phase behavior of the patchy colloids confined in the porous media