Thermal Conductivity of CaSiO$_3$ Perovskite at Lower Mantle Conditions

Thermal conductivity ($κ$) of mantle minerals is a fundamental property in geodynamic modeling. It controls the style of mantle convection and the time scale of the mantle and core cooling. Cubic CaSiO$_3$ perovskite (CaPv) is the third most abundant mineral in the lower mantle (LM) (7 vol%). However, despite its importance, no theoretical or experimental estimate of CaPv's $κ$ exists. Theoretical investigations of its properties are challenging because of its strong anharmonicity. Experimental measurements at relevant high pressures and temperatures are equally challenging. Here we present $ab$ $initio$ results for CaPv's $κ$ obtained using an established phonon quasiparticle approach that can address its strong anharmonicity. We also offer experimental measurements of $κ$. Predictions and measurements are in good agreement and reveal a surprisingly large $κ$ for cubic CaPv. Despite its relatively low abundance, CaPv's $κ$ might increase the lower mantle $κ$ by approximately 10%, if accounted for. $κ$ of mantle regions enriched in crust material will be more strongly impacted.