Crystal structures and phase transitions in minerals to 1 Mbar and beyond

Crystal structure of "post perovskite."


Figure: Crystal structure of "post perovskite." Red spheres are O anions and blue spheres are Mg cations. Si cations reside at the center of the yellow octahedrs. (S. Dorfman)

The transition in MgSiO3 from the perovskite structure to the CaIrO3-type “post-perovskite” structure has important potential implications for understanding the Earth’s long-mysterious core-mantle boundary region that lies 2900 km below the surface. In recent years, we have examined the equation of state, phase boundaries, chemical substitution effects, and deformation behavior of a range of compounds that adopt this structure. Our studies have extended as high as 200 GPa in pressure.

We have many additional projects for examining the crystal structure response to compression in systems of interest for earth sciences, materials science, and condensed matter physics. 

Recent collaborators include S. Shieh (UWO), V. Prakapenka (GSESCARS)

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