On the transferability of interaction potentials for condensed phases of silicon

Abstract

A systematic comparison of structural, thermodynamical and kinetic properties of silicon by molecular dynamics simulation was done using five interatomic potentials, namely the Stillinger-Weber (SW) model, the environment-dependent interatomic potential (EDIP), two versions of the modified embedded-atom method (MEAM-1 and MEAM-2) and the angular dependent potential (ADP). This benchmark allows us to determine which interatomic potential is the most adequate to simulate this material. Structural properties and the vibrational density of states (VDOS) for diamond-structure crystal and amorphous phases were studied. We also obtained the diffusion coefficient for the liquid phase. For the models able to describe crystallization from the melt, the interfacial free-energy was also computed. Results show that the SW potential outperforms the remaining models in several aspects including the structure factor and the coordination number distribution of the liquid and the melting temperature. MEAM-2 follows as the second best model due to its ability to reproduce the crystal-liquid interfacial free-energy and the structure factor and the VDOS for the amorphous phase. EDIP, MEAM-1 and ADP models can reproduce some physical properties but they lack transferability, which is a key aspect of a good interatomic potential.