Dislocation formation from a surface step in semiconductors: an ab initio study

TL;DR

This study uses large-scale first principles calculations to show that surface steps in semiconductors are key sites for dislocation formation and plasticity initiation under stress.

Contribution

It provides new insights into how surface steps influence dislocation formation and plasticity mechanisms in semiconductors through ab initio simulations.

Findings

Surface steps are preferred sites for dislocation initiation.

60° dislocations form and glide under both tensile and compressive stress.

Surface and step termination affect plastic deformation mechanisms.

Abstract

The role of a simple surface defect, such as a step, for relaxing the stress applied to a semiconductor, has been investigated by means of large scale first principles calculations. Our results indicate that the step is the privileged site for initiating plasticity, with the formation and glide of 60$^\circ$ dislocations for both tensile and compressive deformations. We have also examined the effect of surface and step termination on the plastic mechanisms.