Applicability of Embedded Atom Model (EAM) Potentials to Liquid Silicon and Germanium

Abstract

Embedded atom model (EAM) potentials are proposed for liquid silicon and germanium. The potentials are calculated from diffraction data using Shommers’ algorithm and presented in the form of tables and piecewise continuous polynomials. Each pair term contributed to the potential takes the form of a hard-sphere model with a downward step. Properties of liquid Si and Ge (density, energy, bulk modulus, and coefficients of self-diffusion) are calculated at temperatures up to 2000 K and agree well with experimental data. It is found that bond directionality virtually disappears after melting at typical densities of liquid Si and Ge. It is suggested that bond directionality might reemerge upon heating and reducing the melt densities by 200–300%.