Nonlinear Hall signatures of ferroelectric switching in atomically thin WTe₂

Recent experiments have observed nonlinear Hall effects(NLHEs) in atomically thin WTe₂, an ultrathin ferroelectric material which may enable miniaturizing ferroelectric memories. However, signatures of ferroelectricity in NLHEs have remained elusive. In this work, we demonstrate that the direction and magnitude of nonlinear Hall currents can be highly sensitive to the ferroelectric polarization in WTe₂. In particular, there exists a wide experimental regime in which different polarization states are associated with opposite Hall current directions. We point out that such strong NLHE signatures of ferroelectricity originate from polarity-dependent Berry curvature dipoles, which arises from the broken mirror symmetry under strong out-of-plane displacement fields near polarity-switching points. Our work establishes the polarity-dependent NLHE as a novel scheme for fast and nondestructive reading in WTe₂-based ferroelectric memory devices.