New Emergent Quantum States of Matter at High Pressure

在环境条件下，轻碱金属Li、Na和K几乎是自由电子（NFE）金属。但是，当被压缩时，这些金属并没有变得更像自由电子，而是由于离子和电子相互作用中密度驱动的变化，这些金属经历了向不寻常和复杂的结构和电子形式的转变。虽然这种行为在所有高密度物质中都是可以预期的，但由于碱金属在环境条件下的NFE行为以及它们非常高的压缩性，这种物理现象在碱金属中最为明显。因此，它们提供了对所有其他金属在非常高的密度下的行为的独特见解。我们将利用我们团队在实验高压物理学方面的专业知识，以前所未有的密度创造固体和流体碱金属，然后在同步加速器，x射线自由电子激光器和高能激光设施中使用x射线衍射技术确定它们的结构行为。然后，我们将使用电子结构和量子分子动力学计算来理解所观察到的行为背后的物理学，从而对超高密度物质的行为产生新的理解和改进的预测能力。

At ambient conditions, the light alkali metals Li, Na and K are nearly free electron (NFE) metals. But rather than becoming MORE free-electron like when compressed, these metals undergo transitions to unusual and complex structural and electronic forms as a result of density-driven changes in the interactions of the ions and electrons. While such behaviour is expected in all high-density matter, the physics is most evident in the alkali metals due to their NFE behaviour at ambient conditions, and their very high compressibilities. They thus offer a unique insight into the behaviour of all other metals at very high densities. We will exploit our team's expertise in experimental high-pressure physics to create solid and fluid alkali metals at unprecedented densities, and then determine their structural behaviour using x-ray diffraction techniques at synchrotrons, x-ray free electron lasers, and high-energy laser facilities. We will then use electronic structure and quantum-molecular-dynamics calculations to understand the physics behind the observed behaviour, and thereby develop new understanding and improved predictive capabilities in the behaviour of matter at ultra-high densities.