Lattice Thermal Conductivity of MgSiO_(3) Perovskite and Post-Perovskite under Lower Mantle Conditions Calculated by Deep Potential Molecular Dynamics

Lattice thermal conductivity(κlat)of MgSiO_(3) perovskite and post-perovskite is an important parameter for the thermal dynamics in the Earth.Here,we develop a deep potential of density functional theory quality under entire thermodynamic conditions in the lower mantle,and calculate theκlatby the Green-Kubo relation.Deep potential molecular dynamics captures full-order anharmonicity and considers ill-defined phonons in low-κlatmaterials ignored in the phonon gas model.Theκlatshows negative temperature dependence and positive linear pressure dependence.Interestingly,theκlatundergos an increase at the phase boundary from perovskite to post-perovskite.We demonstrate that,along the geotherm,theκlatincreases by 18.2% at the phase boundary.Our results would be helpful for evaluating Earth’s thermal dynamics and improving the Earth model.