Fast Kinetic Monte Carlo Simulation of Crystal Growth and Evolution

University Of Tennessee Knoxville, Knoxville TN

Investigators

Abstract

Schulze 0707443 This project concerns both the development of fast Kinetic Monte-Carlo (KMC) algorithms and their application to simulating nano- and micron-scale crystal growth. Viewed broadly, KMC is the numerical task of simulating stochastic models. While the focus of the project is primarily on crystal growth, KMC simulations arise in many contexts, including micro-magnetics, ecology, and chemical processes. The algorithms that are developed are applicable to all such models. In this work, however, two new algorithms with single event execution times independent of the system size are used to examine dendritic growth during solidification. Dendritic growth refers to a common interfacial instability that occurs during the formation of solid materials -- snow flakes being a familiar example. These instabilities have a number of practical implications for materials processing and are also of fundamental scientific interest. Dendrites that form in both pure and composite materials are studied. This project concerns the development of computer programs that simulate the behavior of solid materials on length scales that are so small that individual atoms are resolved. It therefore has direct impact on the area of nanotechnology, which is rapidly emerging as an area of national strategic interest. The programs that arew developed are the most efficient of all known ways for performing this particular type of simulation. These simulations simulate the growth and evolution of solid phase materials by imitating the random motion of individual atoms using millions of random numbers, which themselves are generated by a separate computer program. A particular type of solid phase growth from a liquid material that gives rise to a snow-flake like crystal structure is a principal area of study, but the computer programs themselves are designed in a way that also makes them useful in a much broader class of problems. Students are involved in the project.