[S-IT23] Structure and Dynamics of Earth and Planetary Mantles

[SIT23-P11] Effect of impurity on post-post-perovskite transition of MgSiO₃ by first principles

*Koichiro Umemoto¹ (1.Earth-Life Science Institute, Tokyo Institute of Technology)

Keywords:super-Earth, post-post-perovskite transition, first principles

Several computational studies have predicted post-post-perovskite transitions in MgSiO3 at ultrahigh pressures and temperatures which can occur at deep interiors of super-Earths: MgSiO₃ --> Mg₂SiO₄+ MgSi₂O₅ --> Mg₂SiO₄+ SiO₂ --> MgO + SiO₂) and recombination (MgO + MgSiO₃ --> Mg₂SiO₄ or SiO₂ + MgSiO₃ --> MgSi₂O₅) [1-5]. As demonstrated in a very recent numerical simulation, these transitions are crucially important in modeling interiors of super-Earths up to 20 times Earth’s mass [6]. However, in the previous studies, these post-post-perovskite transitions were considered only for pure Mg-Si-O. In actual super-Earths, impurities, Fe, Al, or so forth, should exist. Here we will investigate effects of impurities on post-post-perovskite transitions: transition pressures, local atomic structures, and equation of states.



[1] K. Umemoto, R. M. Wentzcovitch, P. B. Allen, Science 311, 983 (2006).

[2] K. Umemoto and R. M. Wentzcovitch, Earth Plent. Sci. Lett. 311, 225 (2011).

[3] S. Q. Wu et al., J. Phys.: Condens. Matter, 26, 035402 (2014).

[4] H. Niu et al., Scientic Reports 5, 18347 (2015).

[5] K. Umemoto et al., Earth Planet. Sci. Lett. 478, 40-45(2017).

[6] A. P. van den Berg et al., Icarus 317, 412-426(2019).