Hybrid Monte Carlo technique for modeling of crystal nucleation and application to lithium disilicate glass-ceramics

We propose a computational method for studying crystal nucleation in glasses and supercooled liquids, combining the techniques of cluster formation via Monte Carlo, Steinhardt order parameter biasing, and an implicit solvation model. Each of these techniques calculates an important contribution to the overall nucleating free energy. This hybrid Monte Carlo technique is applied to the canonical example of a lithium disilicate glass-ceramic, where it is found that the cluster formation and cluster-to-crystal transition energies are approximately equal. The known crystal precursor, lithium metasilicate, has a smaller thermodynamic barrier to nucleation compared to that of lithium disilicate. The solvation energy is small compared to the formation and crystallization energies; yet the metasilicate solvation energy is much lower, indicating easier precipitation compared to the disilicate cluster. Our hybrid Monte Carlo approach is generally applicable to study the nucleation and crystallization processes in any arbitrary glass or supercooled liquid.