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The crystal-melt interface free energy from metadynamics

Date: 28.04.2010
Place: UHW 11/1102

M. Finnis, Materials Theory and Simulation, Department of Materials, Imperial College London, London, UK

The solid-liquid interface free energy is a key parameter controlling nucleation and growth during solidi cation, as well as the energetics of wetting. It is difficult to obtain experimentally, and although there are computational approaches with atomistic simulation,they are difficult to apply routinely. We propose a new approach [1], which is to obtain a free energy map of the phase transition by metadynamics [2]. We have applied this to the benchmark case of a Lennard-Jones potential and the results con rm the most reliable data obtained previously. Our approach o ffers several advantages: it is simple to implement, robust and free of hysteresis problems, it provides a rigorous and unbiased estimate of the statistical uncertainty and a good estimate of the thermodynamic limit, with system sizes of a just a few hundred atoms. It is therefore attractive for using with more realistic and speci fic models of interatomic forces.


[1] S. Angioletti-Uberti, M. Ceriotti, M.W. Finnis and P.D. Lee, Solid-Liquid Interfacial Free Energy from Metadynamics simulations, Phys. Rev. B, to be published
[2] A. Laio and M. Parrinello, Escaping free energy minima, Proc. Natl. Acad. Sci. USA 99: 12562-12566 (2002)

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