Surface eigen-displacement and surface Poisson’s ratios of solids

Theoretical analysis and molecular dynamics simulations were conducted to study systematically surface eigen-displacement and surface Poisson’s ratios of solids, which play essential roles in surface energy, surface strain and surface stress. Face-centered cubic (0 0 1) Au thin films were taken as typical examples to illustrate the physical picture. The surface eigen-displacement is a critical surface strain at the equilibrium state after normal relaxation and thus an intrinsic surface property. Surface Poisson’s ratios are also intrinsic surface properties. Combining surface eigen-displacement and surface Poisson’s ratios with surface eigen-stress and surface tangential elastic constants lays foundations of surface elasticity of solids.

► Surface eigen-displacement is a critical surface strain at the equilibrium state after normal relaxation.
► Surface Poisson’s ratio is the surface excess of Poisson’s ratio.
► Surface eigen-displacement and Surface Poisson’s ratio are surface intrinsic properties.