A molecular dynamics study of the structure of liquid germanium

The structure of liquid Ge as a function of temperature and density was investigated using molecular dynamics and interatomic forces derived from the pseudopotential theory. The authors present results for the pair correlation function, the static structure factor and the bond-angle distribution function as a function of temperature and density. Our results are in good agreement with diffraction experiments. The density derivative of the structure factor deviates from the prediction of the uniform-fluid model due to the density dependence of the interatomic potential. The bond-angle distribution shows that the local order in liquid Ge is different from that of both the semiconducting and the metallic crystalline phases. With progressive undercooling the structure of the liquid does not tend towards the structure of amorphous Ge, because solidification is associated with a metal-semiconductor transition resulting in state-dependent interatomic potentials.