[S-IT22] [EE] 核-マントルの相互作用と共進化

[SIT22-09] Ab initio anharmonic lattice dynamics calculation for Fe-bearing lower mantle minerals

*出倉 春彦¹、土屋 卓久¹ (1.愛媛大学地球深部ダイナミクス研究センター)

キーワード：下部マントル鉱物、格子熱伝導率、コンピュータシミュレーション、フォノン-フォノン相互作用、密度汎関数理論

Determination of lattice thermal conductivity (κ_lat) of lower mantle minerals is key to understanding the dynamics of the Earth’s interior. Although it was impractical in the deep Earth pressure (P) and temperature (T) condition for a long time, recent experimental and computational developments have been extending the accessible P and T ranges. We recently succeeded in developing an ab initio technique to calculateκ_lat at any P and T condition based on the density-functional theory (DFT) combined with anharmonic lattice dynamics theory. The technique was then applied to major end-members of lower mantle minerals, MgSiO₃ bridgmanite (Dekura,Tsuchiya,Tsuchiya,2013,PRL) and MgO periclase (Dekura,Tsuchiya,2017,under review). Next we extend our technique to more realistic Fe-bearing minerals in conjunction with the internally consistent LSDA+U technique (Wang,Tsuchiya,Hase,2015,Nature geoscience) to deal with such strongly-correlated systems. In this presentation, we introduce the current situation of our research on κ_lat .