Switchable moiré potentials in ferroelectric WTe₂/WSe₂ superlattices

Moiré materials with superlattice periodicity many times the atomic length scale have shown strong electronic correlations and band topology with unprecedented tunability. Non-volatile control of the moiré potentials could allow on-demand switching of superlattice effects but has remained challenging to achieve. Here we demonstrate the switching of the correlated and moiré band insulating states, and the associated nonlinear anomalous Hall effect, by the ferroelectric effect. This is achieved in a ferroelectric WTe₂ bilayer of the T_d structure with a centred-rectangular moiré superlattice induced by interfacing with a WSe₂ monolayer of the H structure. The results can be understood in terms of polarization-dependent charge transfer between two WTe₂ monolayers, in which the interfacial layer has a much stronger moiré potential depth; ferroelectric switching thus turns on and off the moiré insulating states. Our study demonstrates the potential for creating new functional moiré materials by incorporating intrinsic symmetry-breaking orders.