Place: Conference on computational physics, Moscow, Russia
A parallel hybrid Monte Carlo/molecular dynamics method is presented for studying segregation of interstitial atoms in the solid state, which is based on the efficient use of virtual atom placeholders as a potential location for interstitials. The algorithm applies an exchange between a randomly chosen virtual atom with a carbon atom and applies a short molecular dynamics trajectory to equilibrate the particles in the local environment, after which an energetic criterion decides about acceptance or rejection of the trial move. Parallelization is done within a manager-worker model and applies a speculative execution of trial moves, which are asynchronously executed on the cores. The technique is applied to an Fe-C system including a dislocation as a symmetry breaking perturbation in the system. It is shown that the parallel scheme is highly efficient and reproduces the findings from sequential runs. To improve efficiency of the stochastic Monte Carlo scheme, a novel biased Monte Carlo scheme is discussed which takes into account the history of the successful particle swaps in the system.