Highly optimized empirical potential model of silicon

摘要

We fit an empirical potential for silicon using the modified embedded atom (MEAM) functional form, which contains a nonlinear function of a sum of pairwise and three-body terms. The three-body term is similar to the Stillinger-Weber form. We parametrized our model using five cubic splines, each with 10 fitting parameters, and fitted the parameters to a large database using the force-matching method. Our model provides a reasonable description of energetics for all atomic coordinations, Z, from the dimer (Z = 1) to fee and hcp (Z = 12). It accurately reproduces phonons and elastic constants, as well as point defect energetics. It also provides a good description of reconstruction energetics for both the 30 degrees and 90 degrees partial dislocations. Unlike previous models, our model accurately predicts formation energies and geometries of interstitial complexes-small dusters, interstitial-chain and planar {311} defects. [References: 62]