We investigate the Earth’s deep interior materials and dynamics with ultra-high pressure and temperature experiments.
We know that the interior of the earth is actually divided into many layers, just like an onion. When you peel away these layers one at a time from the outside in the same way you would peel an onion’s skin, you finally come to the core. The mantle above the core is also divided into four layers, and by 1974 we had identified what the first three layers were made of. When it comes to the lowest layer, the fourth layer, however, there were all kinds of hypotheses but they all remained in the realm of conjecture. This is why I wanted to elucidate the true nature of this material that formed the fourth layer.
PostPerovskite
PostPerovskite phase was discovered in the condition of lowermost lower mantle (the red zone) (Murakami et. al. Science 2004)