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.
For more details see
Thermal conductivity changes across a second-order structural phase transition: the case of high pressure silica, H. Aramberri, R. Rurali, J. Íñiguez. Phys. Rev. B 96, 195201 (2017).
Preprint available in arXiv 1707.05321
