Pressure-Induced Structural Change of Liquid Silicon

Abstract

High-pressure and high-temperature x-ray diffraction measurements indicate that liquid silicon contracts with increasing pressure without significant changes in the local structure up to 8 GPa and then transforms to a denser structure between 8 and 14 GPa. In spite of volume contraction, the nearest-neighbor interatomic distance expands by about 1.6% within this pressure interval, accompanied by an anomalous increase in the coordination number. These findings reveal that the drastic pressure-induced structural change can take place in three-dimensional-network liquids with rather isotropic bonding.