论文标题
在极端条件下亚稳态碳
Metastable Carbon at Extreme Conditions
论文作者
论文摘要
在极端条件下的碳是密集科学探究的重点，因为它对惯性限制融合实验的应用以及了解富含碳的系外行星的内部结构的重要性。在最近的动态压缩实验中发现了钻石在非常高压下的极端亚稳定性。这项工作解决了一个重要的问题，该问题是关于在冲击实验中可能观察到的其他竞争性亚稳态相的存在。发现钻石多型，具有混合立方体和六角形钻石堆叠平面的碳晶体是唯一在100至1,000 GPA之间的压力上，唯一具有能量竞争的碳晶体相。在1 TPA上方，没有发现亚稳态的阶段在热力学稳定的BC8和简单的立方相中具有能量竞争。低焓钻石多型的存在表明，它们可能是碳亚稳态阶段的候选物，出现在钻石的冲击波载荷后出现。
Carbon at extreme conditions is the focus of intensive scientific inquiry due to its importance for applications in inertial confinement fusion experiments and for understanding the interior structure of carbon-rich exoplanets. The extreme metastability of diamond at very high pressures has been discovered in recent dynamic compression experiments. This work addresses an important question about the existence of other competitive metastable carbon phases that might be observed in shock experiments. It was found that diamond polytypes, carbon crystals with mixed cubic and hexagonal diamond stacking planes, are the only metastable carbon crystal phases energetically competitive with cubic diamond at pressures between 100 and 1,000 GPa. Above 1 TPa, no metastable phases are found to be energetically competitive with thermodynamically stable BC8 and simple cubic phases. The existence of low enthalpy diamond polytypes suggests that they are likely candidates for metastable phases of carbon to appear upon shockwave loading of diamond.
