There has been much interest in spin crossovers found experimentally in the most abundant minerals of Earth’s lower mantle ((MgFe)O and (MgFe)(Si,Fe)O₃-perovskite) under pressure. Spin crossovers depend strongly on thermodynamic conditions and a full understanding of this problem requires its investigation as function of pressure and temperature. There are several controversies, especially in the perovskite systems, and surprises are revealed by electronic structure calculations. The geophysical consequences of these crossovers are yet to be fully understood. I will review progress we have made in understanding spin crossovers and give an overview of this phenomenon and its potential implications for the Earth.

Research supported by the US National Science Foundation.

报告人简介：

Renata Wentzcovitch is a Professor of Materials Science and Engineering in the Department of Chemical Engineering and Materials Science at the University of Minnesota. She is a member of the graduate faculties in the School of Physics and Astronomy, Department of Earth Sciences, Chemical Physics Program, and Scientific Computation Program, where she is Director of Graduate Studies. Originally from Brazil, she holds a PhD in Condensed Matter Physics from UC-Berkeley. Over the past two decades her research has been primarily focused on Earth and planetary materials with special emphasis on acoustic/seismic properties of minerals, including those containing iron and undergoing spin state crossovers. She is a fellow of the APS, AGU, MSA, AAAS, and American Academy of Arts and Sciences.