Anomalous phase behavior of first-order fluid-liquid phase transition in phosphorus

作者：Zhao, G.; Wang, H.; Hu, D. M.; Ding, M. C.; Zhao, X. G.; Yan, J. L.

来源：Journal of Chemical Physics, 2017, 147(20): 204501.

DOI：10.1063/1.4999009

• AUGMENTED-WAVE METHOD
• MOLECULAR LIQUID
• SUPERCOOLED SILICON
• ORDER-PARAMETER
• CRITICAL-POINT
• WATER
• DYNAMICS

Although the existence of liquid-liquid phase transition has become more and more convincing, whether it will terminate at a critical point and what is the order parameter are still open. To explore these questions, we revisit the fluid-liquid phase transition (FLPT) in phosphorus (P) and study its phase behavior by performing extensive first-principles molecular dynamics simulations. The FLPT observed in experiments is well reproduced, and a fluid-liquid critical point (FLCP) at T = 3000 similar to 3500 K, P = 1.5-2.0 Kbar is found. With decreasing temperature from the FLCP along the transition line, the density difference (Delta rho) between two coexisting phases first increases from zero and then anomalously decreases; however, the entropy difference (Delta S) continuously increases from zero. These features suggest that an order parameter containing contributions from both the density and the entropy is needed to describe the FLPT in P, and at least at low temperatures, the entropy, instead of the density, governs the FLPT. Published by AIP Publishing.

• 单位
  鲁东大学