Materials Chemistry and Physics of Post-Perovskite Oxides

An important geophysical discovery was made in 2004 when it was shown that MgSiO3 perovskite transforms to a denser 'post-perovskite' phase at ~125 GPa pressure and 2500 K temperature. This phase change provides a good explanation for the existence of the D layer at the base of the Earth's mantle (i.e. at about 2800 km depths), where such extreme conditions prevail. Post-perovskite MgSiO3 has a previously obscure, orthorhombic structure type exemplified by CaIrO3. Very little is known about the physics and chemistry of CaIrO3-type oxides. In addition to the intense mineralogical interest in post-perovskite type oxides, they may have notable electronic or magnetic properties, as their dense but highly anisotropic structure is likely to give rise to strong electron-electron correlations. We propose to explore the substitutional chemistry and physical properties of CaIrO3 and to prepare new analogues at high pressures and temperatures to discover novel materials. The results will be relevant to both the geological and materials communities.