Switchable moire potentials in ferroelectric WTe2/WSe2 superlattices

Moire 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 moire potentials could allow on-demand switching of superlattice effects but has remained challenging to achieve. Here we demonstrate the switching of the correlated and moire 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 moire 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 moire potential depth; ferroelectric switching thus turns on and off the moire insulating states. Our study demonstrates the potential for creating new functional moire materials by incorporating intrinsic symmetry-breaking orders. Intrinsic ferroelectricity in bilayer WTe2 can be used for electrical switching of the centred-rectangular moire potential in WTe2/WSe2 heterostructures.

Automated summary

We have achieved the pulsed control of the superlattice effect in two-dimensional materials through the ferroelectric effect, switching between the correlated and superlattice insulating states, and observing the nonlinear anomalous Hall effect. This study demonstrates the potential for creating new functional superlattice materials by incorporating intrinsic symmetry-breaking orders.