Stability of undissociated screw dislocations in zinc-blende covalent materials from first principle simulations

TL;DR

This study uses first principles simulations to analyze the stability and configurations of perfect screw dislocations in various zinc-blende covalent materials, revealing material-specific core preferences.

Contribution

It provides the first comprehensive first-principles comparison of screw dislocation core structures across multiple zinc-blende materials.

Findings

Shuffle set core configuration is favored in most materials.

Diamond uniquely favors a glide core configuration due to sp$^2$ hybridization.

Results align with low temperature experimental observations.

Abstract

The properties of perfect screw dislocations have been investigated for several zinc-blende materials such as diamond, Si, $\beta$-SiC, Ge and GaAs, by performing first principles calculations. For almost all elements, a core configuration belonging to shuffle set planes is favored, in agreement with low temperature experiments. Only for diamond, a glide configuration has the lowest defect energy, thanks to an sp$^2$ hybridization in the core.