Switchable moiré potentials in ferroelectric WTe₂/WSe₂superlattices

Moiré materials, with superlattice periodicity many times the atomic length scale, have enabled the studies of strong electronic correlations and band topology with unprecedented tunability. However, nonvolatile control of the moiré potentials, which could allow on-demand switching of the superlattice effects, has not been achieved to date. 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 centered-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, which possess very different moiré potential depths; ferroelectric switching thus turns on/off the superlattice. Our study demonstrates the potential of creating new functional moiré materials by incorporating intrinsic symmetry-breaking orders