| アブストラクト |
Ab initio calculation method based on the density functional theory is a very strong research technique originally developed in the solid state physics and now applied to problems in many fields including the Earth and planetary science, in particular in the high-pressure mineral physics. The method provides access to a wide variety of physical and chemical properties non-empirically not only at zero temperature and zero pressure but also at high temperature and high pressure. Presently, calculations are being extended from several fundamental properties such as electronic structure, crystal structure, equation of state, elasticity, thermodynamics, and phase transition, chemical reaction to further larger-scale more complex properties including multi-component properties, transport and mechanical properties.
In this lecture, I will first describe an overview of the high-pressure solid-state physics, including fundaments of the electronic structure theory and ab initio theoretical mineral physics: the band theory combined with the density functional theory which allow us to compute electronic property and static lattice energy of materials, how to deal with the thermal effects (computation of dynamical and thermodynamic property), further extensions from harmonic to higher-order theory, from bulk to polycrystalline property, and from equilibrium to transport property, etc.
Then, I will show some recent progresses on the study of the Earth and planetary materials with major topics on the high-pressure post-perovskite transition and spin crossover transition of dominant silicates and oxides, further challenges to phase relations under extreme multi-megabar planetary pressure condition including post-pyrite transitions of SiO2 with its melting relation and successive transitions in H2O ice, pressure-induced metallization in some oxides, high-pressure transport property including thermal and electrical conductivities of silicates and iron, and also dissolution reactions between liquids and solids. After estimating some key parameters for planetary dynamics such as temperature structure, Rayleigh number, etc. based on the obtained information, new views on the Earth and planetary interiors will be discussed. |
