Nondislocation Origin of GaAs Nanoindentation Pop-In Event

Abstract

The present Letter demonstrates a pop-in event that is caused by a nanoindentation-induced phase transformation in GaAs, and not accompanied by any dislocation nucleation. Our computer simulations reveal the appearance of the new phase, documented by the structural correlation functions and visualization of the atomic positions. This challenges the orthodox view that the initial pop-in event reflects nucleation of dislocations or their movement, and has a bearing on materials where dislocation activity is not present.

Extraction of Plastic Properties of Aluminum Single Crystal Using Berkovich Indentation

“…6(a) is in the range of 67.2-69.5 GPa and in good agreement with values reported in the literature. 21,22) At the indentation depth less than 200 nm, a ''staircase''-shaped P À h curve which is called displacement burst (or ''pop-in'') [23][24][25] is shown in Fig. 3(b).…”

Origin of a Nanoindentation Pop-in Event in Silicon Crystal

“…As a result, the relationship P= dE pot /dh [10] enabled us to determine the P-h curve with pop-ins initiated at indentation depths of h A 9 and h B 10 nm (Fig. 1).…”

Influence of Phase Transformations on Incipient Plasticity of Si-Nanospheres

“…The study of nanoscale deformation when the surface of crystal is subjected to contact stress has proven that initial displacement transient events occurring in metals are the direct result of dislocation nucleation [2]. Our research revealed that this is not always true: instead of dislocation activity, nanoscale deformation may simply be due to phase transformation (semiconductor → metal), as predicted for GaAs by our earlier experiments and atomistic calculations [3]. Using a novel conductive nanoindentation technique, which is highly sensitive to structural changes under pressure [4], we discovered the essential link between this electrical phenomenon (current spike) and the mechanical transient (pop-in) exhibited by GaAs exclusively during nanoscale deformation.…”