Atomic-Scale Investigation of Thermal Conductivity in Lower Mantle Minerals

Constraining heat transport across the core-mantle boundary (CMB) is key to understanding Earth’s thermal evolution and the operation of the geodynamo. This work focuses on the lattice thermal conductivity of the three dominant minerals in the lower mantle—periclase, bridgmanite, and post-bridgmanite—under relevant pressure-temperature-composition conditions. We apply three complementary atomistic simulation methods: the Boltzmann Transport Equation (BTE), Green-Kubo Molecular Dynamics (GKMD), and Non-Equilibrium Molecular Dynamics (NEMD), to study thermal transport up to 150 GPa and 4000 K. The methodology allows cross-validation and provides insights into the role of anharmonicity and length/time scale effects at deep Earth conditions.

Preliminary results for periclase show consistent trends across all three methods and align well with existing data, including the impact of isotopic substitution. For post-bridgmanite, thermal conductivity has been evaluated using both BTE and GKMD over a range of pressures and temperatures, offering initial insight into its anisotropic transport behavior and confirming method consistency. This work lays the foundation for further studies on how compositional variations—such as Fe/Al substitution and spin-state transitions—affect thermal conductivity in deep mantle minerals.