Simulating Non-Equilibrium Processes over Extended Time- and Length-Scales using Parallel Accelerated Dynamics

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TECHNICAL SUMMARY:This award supports computational research and education to develop and apply methods of parallel temperature-accelerated dynamics to enable meaningful simulations of non-equilibrium processes for large system sizes and for long times. The research will build on algorithms for parallel kinetic Monte Carlo developed under an ITR award and will contribute to the cyberinfrastructure of the materials research community. The first applications of spatially parallel temperature-accelerated dynamics will focus on three distinct problems: (1) vacancy formation and annealing in low-temperature metal epitaxial growth, (2) crystalline to amorphous transition in low-temperature semiconductor growth, (3) dynamics of defects after irradiation. The observation of a variety of unexplained phenomena including vacancy formation and strain-induced mound regularization at low temperatures makes the first area particularly interesting. The goal of creating efficient computational algorithms for the simulation of non-equilibrium processes over extended length- and time-scales via temperature accelerated dynamics is likely to have a significant impact on the realistic simulations of a broad variety of materials-related processes and materials. This award also supports related educational and outreach activities. The methods and results developed from this project will also be integrated in part into a joint undergraduate-graduate course on Computational Physics and into a graduate course on Thin-Films and Surface Physics in which students will learn about new theoretical advances and state-of-the-art implementation and empirical evaluation techniques.NON-TECHNICAL SUMMARY:This award supports computational research and education to develop and apply algorithms and software to simulate processes on time scales that are important to the underlying science but out of the range of conventional simulation methods. For example, molecular dynamics is generally limited to nanoseconds because of the small time-step required for the integration of the equations of motion. However, important infrequent events often take place on a time scale of microseconds or even longer. Examples include the evolution of the surface morphology during crystal or film growth, the diffusion of point defects in solids, and the migration of grain boundaries during plastic strain. The PI aims to build on research performed under a previous ITR award to develop new simulation tools. Motivated by experiment, the PI will apply the new methods to materials growth and the dynamics of materials after irradiation. The newly developed algorithms and software will contribute to the cyberinfrastructure of the materials research community.This award also supports related educational and outreach activities. The methods and results developed from this project will also be integrated in part into a joint undergraduate-graduate course on Computational Physics and into a graduate course on Thin-Films and Surface Physics in which students will learn about new theoretical advances and state-of-the-art implementation and empirical evaluation techniques.