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

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)

Selected References:
Duffy, T. S., Some recent advances in understanding the mineralogy of the Earth's deep mantle, Philosophical Transactions of the Royal Society of London A, 366, 4273-4293, 2008.

Shieh, S. R., T. S. Duffy, A. Kubo, G. Shen, V. B. Prakapenka, N. Sata, K. Hirose, and Y. Ohishi, Equation of state of the post-perovskite phase synthesized from a natural (Mg,Fe)SiO3 orthopyroxene, Proceedings of the National Academy of Sciences, 103, 3039-3043, 2006.

Shieh, S. R., A. Kubo, T. S. Duffy, V. B. Prakapenka, and G. Shen, High-pressure phases in SnO2 to 117 GPa, Physical Review B, 73, 014105, 2006.

Duffy, T. S., Synchrotron facilities and the study of deep planetary interiors, Reports of Progress in Physics, 68, 1811-1859, 2005.

Duffy Group
High-Pressure Mineral Physics and Materials Science Laboratory
Department of Geosciences
Princeton University