Nanometre-scale plasticity of Cu(100)

Nanometre-scale indentations on a Cu(100) surface have been performed and characterized by means of atomic force microscopy. Dislocation loops penetrate the surface surrounding the indentation. The surface features of the dislocation loops are consistent with a system of Shockley partials and a stair-rod segment bounding two stacking fault ribbons, as expected from previous experimental and theoretical results for atomic-scale indentations of fcc metal crystals. Plastic yield events during indentation are identified by characteristic discontinuities in the force-distance curves. The stress at the point of first yield is estimated from the measured normal force releasing such discontinuities