Liquid–liquid phase transition in molten cerium during shock release

The identification of the liquid–liquid phase transition (LLPT) in liquids under shock compression is a long-standing challenge. In this Letter, by designing shock-release experiments in shock-driven molten Ce, we observe a first-order LLPT along the release path. The volume change associated with the transition is less than 6%, much smaller than the one (14%) obtained in static compression experiments, indicating that the LLPT in molten Ce is strongly rate dependent. The identified timescale for the LLPT is on the order of 200 ns. Our results, therefore, provide kinetic information of the LLPT in an unprecedented manner, which is extremely valuable for the construction of a non-equilibrium phase diagram.