Applications of accelerated molecular dynamics in materials science: Insights into kinetic processes in complex materials

Blas Uberuaga
Los Alamos National Laboratory
Materials Science and Technology Division

Kinetics are all-important in understand and predicting the time-resolved response of a material to external stimuli, such as irradiation. Molecular dynamics (MD) has become a workhorse in multiple fields to understand kinetic processes at the atomic scale. By allowing the trajectory to explore the system, no assumptions are made about what can happen. However, the key limitation of MD is the accessible time scale. Most experimentally relevant phenomena occur on much longer time scales than the nanosecond-to-microsecond time scales that can be reached by MD.

Over the last 20 years or so, a class of new methods – the so-called accelerated molecular dynamics (AMD) methods – have extended the time scales of direct atomistic simulation while retaining full fidelity to the underlying interatomic interactions. I will describe how these methods have been applied to a number of materials problems, ranging from mass transport in complex oxides to defect evolution near grain boundaries. Even in the simplest of materials, we find new and unexpected kinetic processes that change our understanding. These examples highlight the novel insight that these types of simulations can provide into the kinetic processes that dictate material evolution.

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