Dislocation mechanisms in the first stage of plasticity of nanoindented Au(111) surfaces

The onset of plasticity in Au(111) has been analyzed at the atomic scale. Images of dislocation traces and other features obtained by atomic force microscopy around nanoindentations have been correlated with force vs penetration curves obtained in the same experiment. It has been demonstrated that the discontinuities in force vs penetration curves are associated to the generation and glide of dislocation loops with well-characterized parameters. Half loops intersecting the surface, with screw components, are recognized and processes of cross-slip identified. The formation of terraces and permanent traces around the nanoindentation points has been explained in terms of the elastic theory of dislocations in a continuum.