Lattice dynamical, electronic, and structural properties of complex metals at extreme conditions

我的目标是利用我在光学和x射线光谱学、x射线衍射和第一性原理计算方面的专业知识，对复杂元素金属在极端压力和温度条件下的物理性质有基本的了解。这项研究提出了具有复杂晶体结构的元素金属(如Cs、Rb、Ba、Te)的物理性质，近年来，我们对元素晶体在压力下的结构和成键性质的理解发生了几乎革命性的变化。虽然已经在元素固体中发现了一系列显著和出人意料的复晶结构，但对这些相的物理性质知之甚少。我建议对元素金属复杂相在压力和温度下的极端条件下的晶格动力学和电子性质进行详细的研究。实验研究将基于光谱技术/光学拉曼光谱、非弹性X射线散射光谱以及弥散X射线散射分析的组合，并将与计算工作密切结合。结构方面的X射线衍射研究将在需要的地方补充光谱研究。我将研究在高压下K，Rb，Sr，Ba，Sc，As，Sb，Bi，S，Se，Te和Ga中发现的非常复杂和经常是无公度结构的晶格动力学。除了研究声子软化和声子色散曲线中的其他反常现象外，我还将着手一项雄心勃勃的计划，研究它们的电子性质。我将研究超导相中的超导带隙，以了解配对机制，并渴望探测和表征电子激发谱中的假带隙。总之，这项研究旨在对元素金属在高压下的行为和性质获得基本的新见解，并对导致在压力下意外频繁形成复杂晶体结构的机制形成一致的图景。

I aim to exploit my expertise in optical and x-ray spectroscopy, x-raydiffraction, and first-principles computations to gain fundamental newinsight into the physical properties of complex elemental metals atextreme conditions in pressure and temperature. The research proposed hereconcerns the physics of elemental metals (such as Cs, Rb, Ba, Te) withcomplex crystal structures, where we have witnessed, in recent years, analmost revolutionary change in our understanding of the structural andbonding properties in elemental crystals under pressure. While there hasbeen as series of discoveries of remarkably and unexpectedly complexcrystal structures in elemental solids, very little is known about thephysical properties of these phases.I propose to make detailed studies of the lattice dynamical and electronicproperties of complex phases of elemental metals at extreme conditions inpressure and temperature. The experimental investigations will be based ona combination of spectroscopic techniques / optical Raman spectroscopy,inelastic x-ray scattering spectroscopy, as well as diffuse x-rayscattering analysis /, and will be closely coupled with computationalwork. X-ray diffraction investigations of structural aspects willcomplement the spectroscopic studies where needed. I will investigate thelattice dynamics of the remarkably complex and often incommensuratestructures that have been found in K, Rb, Sr, Ba, Sc, As, Sb, Bi, S, Se,Te and Ga at high pressures. In addition to studies of phonon softeningand other anomalies in their phonon dispersion curves, I will embark on anambitious programme of studies on their electronic properties. I willinvestigate the superconducting gap in superconducting phases to gainunderstanding of the pairing mechanism, and aspire to detect andcharacterise pseudogaps in the electronic excitation spectra. Altogether,this research aims at gaining fundamental new insight in the behaviour andproperties of elemental metals at high pressure and at developing acoherent picture of the mechanisms that lead to the unexpectedly frequentformation of complex crystal structures under pressure.