Charge Density Wave-Induced Highly Sensitive Terahertz Detection Based on a Large Nonlinear Hall Effect

Charge density wave (CDW), a collective mode, hosts rich correlated phenomena, including Mott insulator, quantum spin liquid, and flat band in van der Waals material 1T-TaS₂. Among these, flat bands condense Berry curvature and electronic states into a point of energy, which dramatically amplifies physical effects such as the nonlinear Hall effect (NLHE). Here, we report the observation of a large room-temperature NLHE in the CDW state of 1T-TaS₂ with an estimated Berry curvature dipole of above 10 nm. The zero-diagonal nonlinear transport tensor is revealed despite the presence of C₃ symmetry in the NLHE, which reveals the dynamic coupling of CDW with current. Remarkably, based on the NLHE of 1T-TaS₂, self-powered terahertz detection at 0.1 THz achieves a record responsivity of 69.72 A/W (9060 V/W) and an incident photon-to-electron conversion efficiency of 3.14% at room temperature. Theoretical modeling indicates that flat-band-driven enhanced Berry curvature is attributed to these state-of-the-art NLHE and terahertz detection capabilities. The CDW-induced Mott bandgap protects the NLHE up to room temperature. These findings establish CDW systems as promising platforms for advancing high-sensitivity wireless terahertz detection.