A Novel MnBi 2 Te 4 -Based Terahertz Detector With High-Responsivity at Room Temperature

This letter reports a high-performance room-temperature terahertz (THz) detector, integrating an intrinsic magnetic topological insulator MnBi2Te4with a 3D Σ-shaped metamaterial array. The Σ-array, fabricated via micro-stereolithography, enhances THz wave localization, while MnBi2Te4contributes spin-polarized surface states and ultralow thermal conductivity. Under co-modulation with a 532 nm laser (50 mW/mm2) and a 0.145 mT magnetic field, the detector achieves a responsivity of 8.48 ×105V/W, a noise-equivalent power (NEP) of 27 pW/Hz1/2, and a specific detectivity (D*) of 4 × 109cm·Hz1/2·W-1at 0.1 THz—outperforming commercial Golay cells by a factor of 8.48 in sensitivity. The Σ-array enlarges the active detection area; the laser induces thermoelectric effects via MnBi2Te4’s low thermal conductivity, while the magnetic field prolongs carrier relaxation time by modulating the band gap of topological surface states. The 10×10 mm² device exhibits a millisecond-scale response time and broadband sensitivity (0.1–0.3 THz), enabling potential applications in 6G wireless links and real-time THz imaging.