Comparison between classical potentials and ab initio for silicon under large shear

TL;DR

This study compares classical empirical potentials with ab initio calculations to evaluate their accuracy in modeling large shear deformations in silicon, focusing on stacking fault energies and shear localization.

Contribution

It identifies the Stillinger-Weber potential as the most accurate among tested potentials for large shear in silicon, aligning closely with ab initio results.

Findings

Stillinger-Weber potential best reproduces ab initio shear energy profiles.

Empirical potentials vary significantly in modeling large shear deformations.

Generalized stacking fault energies support the superiority of Stillinger-Weber.

Abstract

The homogeneous shear of the {111} planes along the <110> direction of bulk silicon has been investigated using ab initio techniques, to better understand the strain properties of both shuffle and glide set planes. Similar calculations have been done with three empirical potentials, Stillinger-Weber, Tersoff and EDIP, in order to find the one giving the best results under large shear strains. The generalized stacking fault energies have also been calculated with these potentials to complement this study. It turns out that the Stillinger-Weber potential better reproduces the ab initio results, for the smoothness and the amplitude of the energy variation as well as the localization of shear in the shuffle set.