Semimetal-enabled Rectenna for Sub-THz Wireless Energy Harvesting and Wave-mixing

Topological semimetals, due to their distinctive band structures and topological protection characteristics, show up high mobility and peculiar transport properties, enabling significant nonlinear effects for the efficient technical exploitation at milllimeter-wave/terahertz (THz) range. Here, a layered topological semimetal β-PdBi2 was synthesized via the melt-growth technique, and subsequently integrated with graphene to form an always-on Dirac source (DS) rectenna in terms of van-der Waals integration, leveraging over the unique electronic and mechanical properties of topological semimetals, as well as the efficient thermionic emission without Fermi-level pinning. The rectenna demonstrates exceptional performance metrics across a frequency range from 0.02 to 0.32 THz, in terms of responsivity as high as 805 V/W, fast response time of 163 ns and a noise equivalent power (NEP) as low as 1.03×10⁻11 W/Hz1/2 even at zero-bias, underscores its outstanding performance in low-noise environments. Moreover, the rectenna acts also as a sub-THz mixer, realizing frequency-conversion beyond 100 GHz accompanied with tunable intermediate frequency bandwidth exceeds 53 GHz, rival with state-of-art graphene microwave device. Our strategy provides a universal energy-harvesting building block that become increasingly ubiquitous applications extended through millimeter-wave and terahertz, represent an encouraging advance towards semimetal electronics.