Metasurface‐Engineered Topological WTe ₂ Metadevices for High‐Performance Room‐Temperature Sensing

Terahertz (THz) detection underpins emerging technologies ranging from 6G wireless communication to security screening and ultrafast spectroscopy, requiring devices that deliver high sensitivity, broad bandwidth, and room‐temperature operation. However, conventional THz detection, spanning photonic, electronic, and thermal approaches, suffers respectively from quantum noise and weak absorption at hν < k B T , from carrier transit‐time limitations, and from thermal‐fluctuation noise with slow relaxation, preventing the co‐optimization of zero‐bias operation, bandwidth, and speed. Here, we design a topological metadevice that combines the intrinsic topological quantum properties of type‐II Weyl semimetal WTe 2 with geometrically tailored plasmonic T‐shaped microantennas to achieve dramatically enhanced zero‐bias THz photoresponse. Crucially, the designed asymmetric metadevice architecture simultaneously induces strong local electromagnetic‐field enhancement and macroscopic inversion‐symmetry breaking, thereby amplifying Berry‐curvature–driven nonlinear photoresponse. Experimentally, in direct detection mode, the device exhibits a zero‐bias responsivity exceeding 10 A/W, a noise‐equivalent power (NEP) of 3 pW·Hz −1/2 at 0.3 THz, and a temporal response on the order of 120 ns. In the same platform configured for heterodyne detection, it operates as a broadband terahertz mixer with high intermediate‐frequency (IF) bandwidth of ±26 GHz and −20 dB conversion efficiency.