Studying the solid-melt interface out of equilibrium
© 2015 EPFL
Accelerated sampling molecular dynamics makes it possible to study the structure and energetics of the interface between a crystal and its melt in the undercooled conditions at which solidification occurs.
The properties of the interface between solid and melt are key to solidification and melting, as the interfacial
free energy introduces a kinetic barrier to phase transitions. This makes solidification happen below the melting
temperature, in out-of-equilibrium conditions at which the interfacial free energy is ill defined. In a recently-published paper
(Cheng, Tribello, Ceriotti, Phys. Rev. B 92, 180102(R) (2015))
we draw a connection between the atomistic description of a diffuse solid-liquid interface and its thermodynamic
characterization, resolving the ambiguities in defining the solid-liquid interfacial free energy
above and below the melting temperature. Our analysis
can help reconcile the textbook picture of classical nucleation theory with the growing body of atomistic studies
and mesoscale models of solidification.