First-principles Simulations of Minerals in Earth and Planetary Interiors
In the deep interiors of planets, the pressures and the temperatures are significantly higher than at ambient condition. The interplay between compression and thermal expansion leads to complexity in the chemistry and physical properties of minerals. Improved knowledge of the behavior of dominant minerals inside the Earth and other planets is essential for understanding the structure, dynamics, and evolution of planetary systems.
In this dissertation, I study materials in environments ranging from the deep mantle of the Earth to the core boundary of Jovian planets and to stellar interiors, using computer simulation with first-principles methods. The contents of this dissertation are as follows: Chapters 1-2 provide an overview of Earth and planetary minerals, and a background of first-principles computer simulation methodology. Chapter 3 discusses the thermoelasticity of iron- and aluminum-bearing MgSiO$_3$ in the Earth's lower-mantle. Chapter 4 is about novel phases of hydrogen-oxygen compounds at giant-planet interior conditions. Chapter 5 presents an equation of state of warm dense sodium. We conclude that lower-mantle mineralogy is in accord with the pyrolite model; we demonstrate that minerals can have counter-intuitive stoichiometry and phases at high pressure; and we provide a coherent first-principles equation of state table of sodium in a wide range of density and temperature conditions. This work illustrates the importance of first-principles simulations as powerful tools in Earth and planetary science studies. Finally, chapter 6 discusses possible directions for future work in the field of computational mineral physics.