Optimized many body potential for fcc metals

Abstract

A formalism for optimized many body (OMB) potentials to describe the interatomic interactions in fcc metals is described. The OMB approach is based on the Tersoff potential, widely used to describe covalently bonded materials, and is closely related to the charge optimized many body (COMB) potential formalism for oxides. OMB extends to first nearest neighbors only, and employs a third-order Legendre polynomial to distinguish fcc and hcp structures, the strength of which can be adjusted to match the intrinsic stacking fault energy to arbitrary precision. The potential also predicts generalized stacking fault energy curves that are in very close agreement to the values determined from electronic-structure calculations. This potential is thus well-suited to investigating mechanical properties such as plastic deformation at the atomic scale.

Keywords:

• computer modeling
• interatomic potential
• metals
• simulation

Acknowledgements

We gratefully acknowledge the financial support of the National Science Foundation under grant number DMR-0426870 and the Department of Energy under grant DE-FG02-01ER459-19. We also thank T.-R. Shan for helpful discussions.