Interface-induced Berry-curvature dipole and second-order nonlinear Hall effect in two-dimensional Fe5GeTe2

The second-order nonlinear Hall effect (NLHE), driven by the Berry-curvature dipole (BCD), quantum metrics, and disorder-related mechanisms, have potential in energy harvesting and signal doubling. However, for a large class of known materials, in which inversion symmetry is preserved, the BCD and NLHE are strictly zero. Here, we report that, by interface modulation through AlₓO₃-assisted exfoliation, a strong NLHE is generated in few-layer Fe₅GeTe₂, in which both the BCD and disorder-related contributions are in principle prohibited due to its R3̄m lattice symmetry. Scaling analysis indicates the existence of a large BCD reaching Λ≈1500.25em0exnm. The negative results from Fe₅GeTe₂ devices on SiO₂ substrates confirm that the interface between Fe₅GeTe₂ and AlₓO₃ is responsible for the observed NLHE, revealing an interface-induced BCD, which has never been reported before. Our study provides a feasible way to generate NLHE in materials with inversion symmetry, expanding the material family for NLHE research and inspiring potential applications due to the advantages in mass production.