Berry curvature dipole generation and nonreciprocal spin photocurrents in ferroelectricity polarized heterostructures

Berry curvature dipole (BCD) describes the dipole-like distribution of Berry curvature in momentum space and plays a key role for quantum geometric phenomena in nonlinear optoelectronics. Experimentally, BCD can be generated at artificially designed semiconductor heterointerfaces where rotational symmetry breaking is induced by interfacial lattice mismatch. Such a local interface symmetry breaking strategy is largely limited to the monolayer regime; however, how to induce BCD in thicker semiconductors remains challenging. Here, we demonstrate a strategy for BCD generation in semiconductors beyond the monolayer limit via ferroelectric-polarization-driven symmetry breaking in WSe2/LiNbO3 heterostructures. In contrast to the absence of circular galvanic photocurrent under normal incidence due to the C3 symmetry in WSe2, the in-plane polarization of LiNbO3 in heterostructures breaks the C3 symmetry of WSe2 multilayers into Cs or C1, and induces pronounced circular galvanic photocurrents therein. Importantly, such galvanic photocurrent is nonreciprocal to bias voltage with a giant asymmetry factor of 12. First-principles calculations reveal that the symmetry breaking and energy band reconstruction in multilayer WSe2 induced by polarization field gives rise to a strongly-anisotropic Berry curvature distribution and further generates BCD. Our results on ferroelectricity-driven BCD provide a strategy for engineering quantum geometry in nonlinear optoelectronic devices. Berry curvature dipole (BCD) in 2D materials originates from rotational symmetry breaking and can generate quantum nonlinear optoelectronic phenomena. Here, the authors demonstrate a strategy for BCD and circular photogalvanic effect generation in semiconductors beyond the monolayer limit via ferroelectric-polarization-driven rotational symmetry breaking in WSe2/LiNbO3 heterostructures.