Temperature dependence of the surface free energy and surface stress: An atomistic calculation for Cu(110)

We propose a method to deduce the free energies γ and stresses τ of plane surfaces and solid-liquid interfaces in elemental systems from atomistic simulations involving nonhydrostatically stressed solid phases. The method is applied to compute the temperature dependencies of γ and τ for the (110) Cu surface using Monte Carlo simulations with an embedded-atom potential. Both quantities decrease with temperature but remain different even near the bulk melting point despite extensive premelting of this surface. This difference is explained by the existence in the premelted surface structure of a solid-liquid interface with relatively small but finite values of γ and τ. Separate calculations of the (110) solid-liquid interface stress give a negative value, suggesting that this interface is in a state of compression. This study motivates future work on anisotropy of surface/interface free energies and stresses, and on the extension of this method to more complex systems.