EAGER: Application of Cluster Expansion Method to First-Principles Mineralogy

自2004年以来，人们已经清楚地认识到，在影响地球深处主要矿物的两种不同晶体结构之间存在着过渡。地球的地幔，也就是距地核边界200公里以内的地方。这种钙钛矿到后钙钛矿过渡的实验研究是具有挑战性的，零碎的，当包括铁时，相互矛盾。这项EaGER奖励将使初步的计算研究能够补充一些正在进行的实验工作。将采用必要的方法来了解具有许多可能的原子排列的矿物，这些方法在现代材料科学中广泛使用，但在矿物物理学中鲜为人知。矿物学界似乎很少了解正确处理固溶体中原子排列的重要性，无论是对于获得构型熵还是它对振动项的影响；计算矿物物理学的许多研究将受益于提高对固体溶液的认识水平和提供解决这些问题的工具。这项工作旨在证明它们适合于下地幔矿物学的详细后续研究，并引发一场将第一原理方法扩展到单组分系统之外的革命，同时培养一名在计算热力学、实验矿物物理、观测天文学和理论地球物理流体动力学方面具有广泛能力的研究生。

Since 2004, it has become clear that there is a transition between two different crystal structures affecting the major mineral present deep in the Earth?s mantle, or, within about 200 km of the boundary with the Earth's core. Experimental studies of this perovskite to post-perovskite transition are challenging, fragmentary and, when iron is included, mutually contradictory. This EaGER award will enable a preliminary computational study to complement some ongoing experimental efforts. Methods necessary to understand minerals with many possible atomic arrangements, widespread in modern materials science but little known in mineral physics, will be employed.The importance of proper treatment of atomic arrangements in solid solutions, both for obtaining the configurational entropy and in its effect on the vibrational terms, seems to be little understood in the mineralogical community; many studies in computational mineral physics will benefit from raising the level of awareness of solid solutions and the availability of tools to address them. This work is intended to demonstrate their suitability for detailed follow-up studies of lower mantle mineralogy and also to spark a revolution in extension of first-principles methods beyond one-component systems, while training a graduate student with broad abilities in computational thermodynamics, experimental mineral physics, observational astronomy, and theoretical geophysical fluid dynamics.