The recently unfolded ferroionic phenomena in 2D van der Waals (vdW) copper–indium–
thiophosphate (CuInP2S6 or CIPS) have received widespread interest as they allow for
dynamic control of conductive switching properties, which are appealing in the paradigm‐
shift computing. The intricate couplings between ferroelectric polarization and ionic
conduction in 2D vdW CIPS facilitate the manipulation and dynamic control of conductive
behaviors. However, the complex interplays and underlying mechanisms are not yet fully …

In article number 2302419, Yishu Zhang, Yang Xu, Bin Yu, and co-workers report the
fabrication of a full 2D van der Waals heterostructure ferroelectric semimetal junction to
unravel the conductive mechanism of CuInP 2 S 6, and present a detailed phase diagram of
the competing mechanisms and transition boundaries with temperature and an external
electric field. Based on this understanding, an artificial synapse with automatic gain control
is demonstrated.