Structural Changes of Short- and Intermediate-Range Order in Liquid Arsenic under Pressure

The pressure dependence of the structural properties of liquid arsenic (l-As) is studied in detail by ab initio molecular dynamics simulations and X-ray diffraction experiments. In this study, we have clarified that network structures consisting mainly of As-4 units exist at lower pressures and that the correlation between the As-4 units is the origin of an intermediate-range order, which is seen as a prepeak of the static structure factor. When the pressure increases, the intermediate-range order disappears and structural change occurs gradually. At approximately 7 GPa, the pair distribution function and the bond angle distribution show some similarities to those of the simple cubic structure as seen in the high-pressure phase of crystalline As.