We study the pressure dependence of the structural and electronic properties of liquid AsS by ab initio
molecular dynamics simulations.We confirm that liquid AsS consists of As4S4 molecules at ambient pressure, as
in the crystalline state.With increasing pressure, a structural transition from molecular to polymeric liquid occurs
near 2 GPa, which is eventually followed by metallization. The pressure dependence of the density and diffusion
coefficients changes qualitatively with this transition. We find that, during metallization in the polymeric phase
at higher pressures, the remnants of covalent interactions between atoms play an important role in the dynamics,
i.e., the As-S bond length becomes longer with increasing pressure and the diffusion coefficients have a local
maximum near 5 GPa. When the pressure approaches about 15 GPa, the covalent nature of the liquid becomes
quite weak. These results explain recent experiments on the pressure dependence of the viscosity.
雑誌名
Physical Review B : Condensed Matter and Materials Physics
Polymerization transition in liquid AsS under pressure: An ab initio molecular dynamics study
PhysRevB.84.224202_l-AsS-underP.pdf
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