First-principles study on mechanical and magnetic properties of the perovskite and post-perovskite polymorphs of pure end-member FeSiO₃ at the core–mantle boundary

Abstract

We obtained wave velocities of FeSiO₃ within perovskite and post-perovskite phases at 130 GPa by first-principles calculations in order to understand the abrupt reduction in seismic velocity at the core–mantle boundary. Our results proved that high iron density significantly reduces the seismic velocity. The elastic anisotropy, electronic structure and chemical bonding of FeSiO₃ in perovskite and post-perovskite phases are extensively explored to illustrate the variation of mechanical and magnetic properties with pressure. Magnetic collapse was predicted in the perovskite phase, which is attributed to the pressure-induced broadening of 3d valence bands of iron.

Keywords:

• high pressure
• FeSiO₃
• core–mantle boundary

Acknowledgements

We are thankful for the financial support from the National Natural Science Foundation of China (NSFC) under grant no. 10874054, the NSFC awarded Research Fellowship for International Young Scientists under grant no. 10910263, the research fund for Excellent Young Scientists in Jilin University (no. 200905003), the China 973 Program under grant no. 2005CB724400, and the 2007 Cheung Kong Scholars Program of China.