N-body potential for simulating lattice defects and diffusion in copper

Abstract

We present a new classical interatomic potential for molecular dynamics simulations of copper. The potential was developed within the N-body approach, which, in addition to pair and many-body interactions, can take into account three-body ones with the required precision. Our potential accurately predicts a wide range of properties of copper: structural, elastic, point and planar, and thermal such as melting point. The latter is essential for the proper reproduction of the homologous temperature and comparison of the calculated results with the corresponding experimental data, such as diffusion coefficients. The potential predicts the intrinsic stacking fault energy within the range of experimental measurements, which indicates its ability to correctly describe the deformation behavior of copper. In this work, we performed simulations of lattice and grain-boundary diffusion of copper with our potential. It shows a moderate overestimation of the lattice diffusivity with a deviation less than one order of magnitude. To simulate the grain boundary diffusion, we built a general-type grain boundary employing the original method. The calculated grain-boundary diffusivity is in remarkable agreement with the literature data and almost coincides with them at higher temperatures in the considered temperature range. The constructed potential can be effectively used for molecular dynamics simulations of defect properties and diffusion phenomena and composing the interatomic potentials within the N-body approach for alloys containing copper.