Department of Materials Science, Royal School of Mines, Thomas Young Center, London Centre for Nanotechnology, Imperial College London, London SW7 2AZ, United Kingdom.
Dynamics of Condensed Matter, Department of Chemistry, University of Paderborn, Warburger Strasse 100, D-33098 Paderborn, Germany and Paderborn Center for Parallel Computing and Institute for Lightweight Design with Hybrid Systems, University of Paderborn, Warburger Strasse 100, D-33098 Paderborn, Germany.
J Chem Phys. 2017 Feb 28;146(8):084503. doi: 10.1063/1.4976836.
We revisit the enthalpy-pressure phase diagram of the various products from the different proposed decompositions of HS at pressures above 150 GPa by means of accurate diffusion Monte Carlo simulations. Our results entail a revision of the ground-state enthalpy-pressure phase diagram. Specifically, we find that the C2/c HS structure is persistent up to 440 GPa before undergoing a phase transition into the C2/m phase. Contrary to density functional theory, our calculations suggest that the C2/m phase of HS is more stable than the I4/amd HS structure over the whole pressure range from 150 to 400 GPa. More importantly, we predict that the Im-3m phase is the most likely candidate for HS, which is consistent with recent experimental x-ray diffraction measurements.
我们通过精确的扩散蒙特卡罗模拟，重新研究了在 150GPa 以上压力下，HS 不同分解产物的焓-压相图。我们的结果需要对基态焓-压相图进行修订。具体来说，我们发现 C2/c HS 结构在经历向 C2/m 相的相变之前，一直持续到 440GPa。与密度泛函理论相反，我们的计算表明，在 150 到 400GPa 的整个压力范围内，HS 的 C2/m 相比 I4/amd HS 结构更稳定。更重要的是，我们预测 Im-3m 相是 HS 最有可能的候选相，这与最近的实验 X 射线衍射测量结果一致。
