Experimental and theoretical studies of phase-change Ge-Sb-Te alloys in the liquid state

这项研究的总体目标是使人们对Ge-Sb-Te相变合金在液态中的结构和动力学性质以及它们在原子尺度上作为成分和温度的函数的行为有一个大致的了解。这些目标将有助于理解相变现象，这对于液体半导体的物理学和开发用于非易失性数据存储介质的具有定制性能的相变材料具有非常重要的意义。项目目标将通过结合最先进的实验方法实现，例如高能同步X射线衍射、X射线吸收光谱、中子衍射、粘度计和密度计量学，以及建模技术，例如基于密度泛函理论的从头计算分子动力学模拟和反向蒙特卡罗模拟。我们还将用从头算分子动力学方法研究电子激发对晶态向过冷液相转变的影响。通过将我们的结果与现有的关于非晶相和晶相的实验和理论工作进行比较分析，将提供对Ge-Sb-Te合金的熔化、非晶化和晶化的洞察。

The overall goal of this investigation is to bring about a general understanding of the structural and dynamical properties of Ge-Sb-Te phase-change alloys in the liquid phase and of their behaviour on the atomic scale as a function of composition and temperature. These goals will contribute to the comprehension of the phase-change phenomenon, which is of high importance for the physics of liquid semiconductors and for the development of phase-change materials with tailored properties for applications in non-volatile data storage media. The project goals will be achieved by a combination of state-of-the-art experimental methods, such as high-energy synchrotron X-ray diffraction, X-Ray absorption spectroscopy, neutron diffraction, viscometry, and densitometry, and modelling techniques, such as ab initio molecular dynamics simulations based on density functional theory and reverse Monte-Carlo simulations. The effects of electronic excitations on the transition from the crystalline to the supercooled liquid phase will also be studied by ab initio molecular dynamics simulations. Insight on the melting, amorphization and crystallization of Ge-Sb-Te alloys will be provided by a comparative analysis of our results with existing experimental and theoretical work on the amorphous and crystalline phases.