The indentation of a metal surface was modelled by combining an atomistic metal with a hard-sphere indenter. This yielded atomistic imaging of dislocation nucleation during displacement-controlled indentation on a passivated surface. Dislocations and defects were located, and imaged by, local deviations from centrosymmetry. On a (111) surface, the nucleation of partial dislocation loops occurred below the surface; within the indenter contact area. The observations were compared with empirical criteria for dislocation nucleation, and with the corresponding continuum elasticity solutions.

Dislocation Nucleation and Defect Structure during Surface Indentation. C.L.Kelchner, S.J.Plimpton, J.C.Hamilton: Physical Review B, 1998, 58[17], 11085-8