Influence of strain on dislocation core in silicon

Abstract

First principles, density functional-based tight binding and semi-empirical interatomic potentials calculations are performed to analyse the influence of large strains on the structure and stability of a 60 dislocation in silicon. Such strains typically arise during the mechanical testing of nanostructures like nanopillars or nanoparticles. We focus on bi-axial strains in the plane normal to the dislocation line. Our calculations surprisingly reveal that the dislocation core structure largely depends on the applied strain, for strain levels of about 5%. In the particular case of bi-axial compression, the transformation of the dislocation to a locally disordered configuration occurs for similar strain magnitudes. The formation of an opening, however, requires larger strains, of about 7.5%. Furthermore, our results suggest that electronic structure methods should be favoured to model dislocation cores in case of large strains whenever possible.

Keywords:

• Dislocations
• silicon
• strain
• density functional theory
• tight binding
• interatomic potential

Notes

No potential conflict of interest was reported by the authors.

1 The MEAM potential we use in this work is a slightly modified version of the potential published in Ref. [60], with the following parameters: , , .

Additional information

Funding

All calculations have been performed using the supercomputer facilities at the Spin Center at the University of Poitiers. The authors acknowledge the support of the French Agence Nationale de la Recherche (ANR), [grant ANR-12-BS04-0003] (project BIDUL).