P-T-V data for liquid Fe-S alloys
Description
P-T-V data for liquid Fe-S alloys (S = 0, 5.5, 11.5 and 18.1 wt. %) at pressure from about 130 ~ 330 GPa and temperature by 4000 ~ 6000 K by first-principles molecular dynamics (FP-MD) simulations. FP-MD are based on the density functional theory (DFT) as implemented in the Vienna Ab initio Simulation Package (VASP) (Kresse & Furthmüller, 1996; Kresse & Hafner, 1993). The exchange-correlation functional is the Perdew-Burke-Ernzerhof (PBE) (Perdew et al., 1996) variant of the generalized gradient approximation (GGA). Valence electrons states are expanded into plane waves with a cutoff energy of 500 eV. The finite temperatures for electronical structure and force calculations are implemented within the Fermi-Dirac smearing (Mermin, 1965). The reciprocal Brillouin zone is sampled by gamma point. These setting values are sufficient to produce converging results. Molecular dynamics runs have been performed in the canonical ensemble (NVT) using Nosè-Hoover thermostat (Hoover, 1985; Nosé, 1984) to control the temperature. Every simulation runs for 7 ps with timesteps of 1.0 fs. The first 2 ps are to reach the equilibrium. P, T and V values are averaged statistically from the last 5 ps. The running steps are enough to collect accurate averages.