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

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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.