Anomalous plastic deformation at surfaces: Nanoindentation of gold single crystals

Nanoindentation data on single-crystal Au(111), Au(110), and Au(100) are presented and show an interesting yielding phenomenon---this yielding behavior is composed of a series of discrete yielding events separated by elastic deformation. The onset of this behavior is in agreement with calculations for the theoretical shear strength of gold. Good quantitative agreement is found between the experimental results and a model developed for the nucleation and multiplication of dislocations by a simple Frank-Read source under the indenter tip.