The microscopic mechanism of the metallization of liquid selenium under pressure is studied by ab initio molecular dynamics simulations. From the obtained electronic properties, such as the electronic density of states and the bond-overlap population, the pressure-induced metallization is found to be completed at a pressure of approximately 5 GPa, in agreement with recent experimental observations. When the pressure exceeds 5 GPa, the nearest-neighbor distance and the coordination number increase drastically with increasing pressure up to 10 GPa. An important finding is that, during this structural change, there is a microscopic competition between metalliclike and covalentlike interactions, which results in a peculiar atomic structure in this pressure range. The pressure dependence of the self-diffusion coefficient is in qualitative agreement with that of the experimental share viscosity. A comparison with the static structure of liquid tellurium under pressure is also discussed.

• Received 13 January 2011

DOI:https://doi.org/10.1103/PhysRevB.83.134206