A concise, efficient and accurate method for calculating the solid-liquid interfacial free energy

Abstract

The solid-liquid (SL) interfacial free energy (IFE) is a pivotal property in many scenarios in physics, chemistry and even materials science. However, current experimental measurements and theoretical calculations of the SL IFE still suffer from problems of conciseness, efficiency and, above all, accuracy. For example, the currently dominant theoretical ‘3C’ methods, i.e. the cleaving potential method (CPM), the capillary fluctuations method (CFM) and the critical nucleus method (CNM), give results for the same SL interface that differ with each other by tens of per cent. In addition, these ‘3C’ methods are all computationally intensive. In this communication, we propose a new stable interface method (SIM) for the calculation of the SL IFE, which is concise, efficient and accurate at the same time. Based on the lever law in the isoenthalpic-isobaric phase diagram and the minimum interface principle, we can artificially control the morphology of the stable SL interface with different mean curvature in molecular dynamics simulations. The excellent agreement of the application results with the Gibbs-Thomson equation illustrates the accuracy of SIM, and hence the calculated SL IFE. The computational framework of SIM demonstrates the conciseness and the ultra-high computational efficiency. By applying SIM to three representative metals, it is demonstrated that SIM is superior to current ‘3C’ methods in terms of conciseness, efficiency and, in particular, accuracy. Finally, due to the universality of the mechanisms, this method should also be applicable to various materials, such as non-metals.