Ultrafast Imaging of Dynamic Disorder in Superionic Chalcocite

The optimal functionalities of matter often appear at emergent structural orders involving entangled changes in the lattice structures and the underlying atomic degree of freedom. Here, we report laser-induced, thermally driven dynamic structural orders evolving in the low- to high-chalcocite transition of copper(I) sulfide using time-resolved electron diffractometry in ultrafast electron microscopy. We filmed the complete phase trajectory of the transient atomic motions and the hierarchical decoupling of structural orders that unfold over time. Moreover, a transient, disordered state is unveiled. The disordered state emerges during the superionic diffusion of copper ions along a few-nanometer-thick lattice channels. Temporal gating of the various combinations of structure could expand the range of accessible functional states in matter.