Environment-dependent interatomic potential for bulk silicon

Abstract

We use recent theoretical advances to develop a new functional form for interatomic forces in bulk silicon. The theoretical results underlying the model include a novel analysis of elastic properties for the diamond and graphitic structures and inversions of ab initio cohesive energy curves. The interaction model includes two-body and three-body terms which depend on the local atomic environment through an effective coordination number. This formulation is able to capture successfully: (i) the energetics and elastic properties of the ground state diamond lattice; (ii) the covalent re-hybridization of undercoordinated atoms; (iii) and a smooth transition to metallic bonding for overcoordinated atoms. Because the essential features of chemical bonding in the bulk are built into the functional form, this model promises to be useful for describing interatomic forces in silicon bulk phases and defects. Although this functional form is remarkably realistic by usual standards, it contains a small number of fitting parameters and requires computational effort comparable to the most efficient existing models. In a companion paper, a complete parameterization of the model is given, and excellent performance for condensed phases and bulk defects is demonstrated.

Molecular dynamics of single-particle impacts predicts phase diagrams for large scale pattern formation

“…Because this method is computationally expensive for large targets, we first constructed a smaller 10×10×10 nm 3 block, and then copied it four times to achieve the desired size. The resulting composite was then annealed with the environment-dependent interatomic potential 32 . This gives an optimized amorphous structure with realistic density, and in which most of the Si atoms have coordination number 4.…”

Detailed microscopic analysis of self-interstitial aggregation in silicon. II. Thermodynamic analysis of single clusters

“…The various predicted structures were found to be in excellent structural agreement with microscopy observations and electronic-structure calculations. [2][3][4][5][6][7] Overall, the three different potentials employed, namely, the environment-dependent interatomic potential ͑EDIP͒, 8 Tersoff, 9 and Stillinger-Weber ͑SW͒, 10 all predicted consistent overall trends, leading to a qualitatively coherent picture for some aspects of selfinterstitial clustering in silicon. In particular, it was found that cluster morphology is sensitively dependent on both the temperature and stress within the lattice.…”

Comparison of molecular dynamics and binary collision approximation simulations for atom displacement analysis

“…The sizes of the cells were chosen to fully enclose the developing cascade within a single cell. The amorphous Si structure was optimized using the algorithm of Wooten, Winer, and Weaire (WWW) [36] and subsequently relaxed using the EDIP. This method gives reasonably optimized amorphous structure with realistic density, where there are almost no coordination defects in the initial structure [37].…”