Solid-liquid metal interface definition studies using capillary fluctuation method

Abstract

We present a review of various commonly used numerical approaches used to define the interface of a crystal-melt structure at the atomic scale using order parameters, local positioning and density functions. The effectiveness and deviations in interfacial stiffness, as calculated through the capillary fluctuation method, are compared between two methods, centrosymmetry parameter and the local concentration parameter, for the face-centered cubic structure of aluminum. In addition, a new maximum difference filtering technique is introduced that uses existing order parameters to create finely detailed interfaces between two phases. The filtering technique is used to define various fractal scales at the interface, and to demonstrate the effect on interfacial stiffness due to the change in scale on the fluctuation analysis for a range of wavenumbers. The presented material is intended for applications of the capillary fluctuation method where the consistent and automatic definition of two-phase interfaces is required for a large number of atom coordinate configurations.