Accelerated molecular dynamics simulation of large systems with parallel collective variable-driven hyperdynamics

S Fukuhara and KM Bal and EC Neyts and Y Shibuta, COMPUTATIONAL MATERIALS SCIENCE, 177, 109581 (2020).

DOI: 10.1016/j.commatsci.2020.109581

The limitation in time and length scale is a major issue of molecular dynamics (MD) simulation. Although several methods have been developed to extend the MD time scale, their performance usually deteriorates with increasing system size. Therefore, an acceleration method which is applicable to large systems is required to bridge the gap between the MD simulations and target phenomena. In this study, an accelerated MD method for large system is developed based on the collective variable- driven hyperdynamics (CVHD) method K.M. Bal and E.C. Neyts, 2015. The key idea is to run CVHD in parallel with rate control and accelerate multiple possible events simultaneously. Using this novel method, carbon diffusion in bcc-iron bicrystal with grain boundary is examined as an application for practical materials. Carbon atoms reaching at the grain boundary are trapped whereas carbon atoms in the bulk region diffuse randomly, and both dynamic regimes can be simultaneously accelerated with the parallel CVHD technique.

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