Stm Observation of Dislocation Configurations Movement by Nanoindentation

Nanoindentation has proved to be a technique capable of elucidating the mechanical properties of solid surfaces. Along with recent studies [1,2], our investigation deals with the initial stages of plastic deformation in a solid. In previous works [3,4] we have recognized and characterized by scanning tunneling microscopy (STM) the generation around a nanoindentation trace in Au(001) of two types of dislocation configurations: a) ‘mesa’-shaped dislocation configurations (named as ‘hillocks’) and b) ‘screw-loops’, dislocation loops consisting of segments with a screw component that can wind up creating terraces. Both types of dislocation configurations can be accounted for in terms of the elastic theory of dislocations in a continuum [3,4] and of simulations based on molecular dynamics [3].