Direct observation of shock-induced formation of davemaoite, Ca-perovskite

Perovskite-structured silicates are key minerals of Earth's lower mantle and have also been identified in shocked meteorites as the (Mg,Fe)SiO₃-perovskite phase, bridgmanite. In contrast, CaSiO₃-perovskite (davemaoite) has never been found in meteorites and is known only from rare inclusions in deep-mantle diamonds. This contrast highlights a fundamental gap: while natural samples provide indirect evidence for silicate perovskites under shock conditions, laboratory dynamic compression experiments have yet to directly capture perovskite transitions in either MgSiO₃ or CaSiO₃, likely due to kinetic limitations imposed by nanosecond timescales. Here we present the in situ, atomic-scale observations of CaSiO₃-perovskite formation under dynamic compression. Using nanosecond laser-driven shocks and ultrafast X-ray diffraction (XRD) at SACLA, we tracked the transformation of CaSiO₃ from low-pressure phases to an amorphous state, and ultimately to davemaoite above ~91(10) GPa, suggesting a disorder-order transformation pathway toward reconstructive crystallization on nanosecond timescales. Upon release, davemaoite undergoes amorphization via a transient low-symmetry phase. These observations provide direct structural evidence for silicate perovskite formation under dynamic loading, resolving a long-standing experimental problem and establishing dynamic compression as an effective route to probe deep-mantle minerals relevant to Earth and Ca-rich exoplanet interiors.