Fig. 1: Progress of polarization switching in different ferroelectrics.

a Diagram of polarization switching in a single crystal, where domain coalescence dominates the switching process and is described by the KAI model. b Diagram of polarization switching in polycrystalline ferroelectrics, where domain nucleation dominates the switching process and follows the NLS model. c Diagram of polarization switching in ferroelectric superlattice, where individual ferroelectric layers can be switched layer-by-layer. d Diagram of anomalous polarization switching in CIPS. While Cu ions undergo intralayer hopping and interlayer hopping progress during the migration, polarization alignment with and against the applied electric field occurs sequentially. e Time-dependent changing polarization of KAI model, with a constant of switching time t₀. f Time evolution of changing polarization based on the NLS model, where switching time is characterized by the Lorentzian function. g Time-dependent changing polarization in ferroelectric superlattices, where a quadruple-peak function determined by four individual ferroelectric layers is responsible for the distribution of switching time. h Time-dependent changing polarization in CIPS, where intralayer and interlayer switching associated double-peak function is responsible for the distribution of switching time.