Chain structure of liquid Se at high temperature and pressure investigated by ab initio molecular dynamics simulations

Using ab initio molecular dynamics simulations, the local atomic structural, dynamic and electronic properties of liquid selenium were studied under different temperatures and pressures. Compared with experimental data, the calculated structure factors and viscosities are acceptable on the whole. Our results indicate that the chain structure of crystalline selenium still exists in liquid state even at high temperature and pressure. The fraction of twofold-coordinated atoms decreases obviously under high pressure while it remains nearly invariable with the increase of temperature. The Peierls-type distorted structures in trigonal Se still reserve in liquid state even under high temperature and pressure. The calculated DOS displays an obvious dip at E_F, and the dip becomes shallower with rising temperature.