Ab initio Lattice Thermal Conductivity of MgSiO_3 Perovskite as Found in Earth's Lower Mantle

摘要

The lattice thermal conductivity (K_(lat)) of MgSiO_3 perovskite (Mg-Pv) under high-pressure and high-temperature conditions was computed based on the ab initio anharmonic lattice dynamics method with the density functional perturbation theory. K_(lat) of Mg-Pv is found to increase with increasing pressure from 9.8 (at 23.5 GPa) to 43.6 Wm~(-1) K~(-1) (at 136 GPa) at 300 K, while decreasing with increasing temperature from 28.1 (at 300 K) to 2.3 W m~(-1) K~(-1) (at 4000 K) at 100 GPa. A multiphase composite average yielded a mantle Rayleigh number adequate to promote the vigorous thermal convection of the mantle that is expected geophysically.