Wednes. seminar

[Cond.Matt. & Stat.Mech.Section]

  JOINT ICTP/SISSA CONDENSED MATTER SEMINAR





Luigi Stasi Seminar Room -   ICTP Leonardo Building   (first floor)



Wednesday, 31 March -     4:00 p.m.



Michael W. FINNIS      ( Imperial College London )



"The crystal-melt interface free energy   from metadynamics



Abstract



The solid-liquid interface free energy is a key parameter controlling  
nucleation and growth during solidification, 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  confirm the most reliable data obtained  
previously.  This approach offers 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 of the thermodynamic limit  with system sizes of a  
just a few hundred atoms.  It is therefore attractive for using with  
more realistic and specific 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)