(220e) Estimation of Nucleation Barriers for Colloidal Crystals from Computer Simulations

One of the most prevalent phase transformations in nature is the nucleation of crystals from fluid phases and their growth. Applications range from ice crystal formation in the atmosphere, to metallurgy, nanomaterials, and protein crystallization. Despite its overwhelming importance, the details of crystal nucleation remain poorly understood. In classical nucleation theory, the barrier of homogeneous nucleation is given by two contributions, the energy gain of creating a nucleus and the energy loss due to surface tension of the new created interface. While nuclei are in general non spherical and have anisotropic interfacial tension, the classical nucleation theory neglects those effects.

In this talk, we present a method to calculate nucleation barriers from Monte Carlo simulations without the need to precisely locate the interface or to compute the anisotropic interfacial tension [Statt, Antonia, Peter Virnau, and Kurt Binder. Phys. Rev. Lett. 114.2, 026101 (2015)]. As a test case, we investigate a soft extension of the well-known effective Asakura−Oosawa model for colloid−polymer mixtures [Dijkstra, Marjolein, René van Roij, and Robert Evans. Phys. Rev. E 59.5, 5744 (1999)]. While our analysis is appropriate for crystal nuclei of arbitrary shape, we find the nucleation barrier to be compatible with a spherical shape and mostly consistent with classical nucleation theory.