High pressure silica

Silicon dioxide is the most abundant compound on Earth. We have investigated the thermal properties of SiO₂ as it undergoes a pressure-induced phase transition from the stishovite phase to the CaCl₂-type phase. We found an astonishingly large peak of the in-plane thermal conductivity close to the critical pressure due to an increase in the population of acoustic modes. Since these two high pressure phases of SiO₂ naturally occur inside the Earth's mantle, we also computed the lattice thermal conductivity of silica along the geotherm.