Colossal Room‐Temperature Terahertz Topological Response in Type‐II Weyl Semimetal NbIrTe4

The electromagnetic spectrum between microwave and infrared light is termed the “terahertz (THz) gap,” of which there is an urgent lack of feasible and efficient room‐temperature (RT) THz detectors. Type‐II Weyl semimetals (WSMs) have been predicted to host significant RT topological photoresponses in low‐frequency regions, especially in the THz gap, well addressing the shortcomings of THz detectors. However, such devices have not been experimentally realized yet. Herein, a type‐II WSM (NbIrTe4) is selected to fabricate THz detector, which exhibits a photoresponsivity of 5.7 × 104 V W−1 and a one‐year air stability at RT. Such excellent THz‐detection performance can be attributed to the topological effect of type‐II WSM in which the effective mass of photogenerated electrons can be reduced by the large tilting angle of Weyl nodes to further improve mobility and photoresponsivity. Impressively, this device shows a giant intrinsic anisotropic conductance (σmax/σmin = 339) and THz response (Iph‐max/Iph‐min = 40.9), both of which are record values known. The findings open a new avenue for the realization of uncooled and highly sensitive THz detectors by exploring type‐II WSM‐based devices. With development of room‐temperature (RT) terahertz (THz) detectors, layered materials with topological band structure have stimulated burgeoning research interest. In this work, type‐II Weyl semimetal NbIrTe4 is applied in RT THz detection, which, compared with other known layered materials, exhibits the highest photoresponsivity, the largest anisotropic ratio of intrinsic conductance and THz photocurrent, and excellent air stability.