High-performance terahertz detection in Weyl semimetal NbP nanosheets

Abstract

Weyl semimetals (WSMs), with their unique electronic structures and topological properties, have garnered significant interest for transport and optoelectronic applications. Among them, Type-I Weyl semimetal NbP exhibits high carrier mobility and strong nonlinear optical responses, making it a promising candidate for infrared and terahertz (THz) detection. However, challenges in conventional thin-film fabrication have limited the practical integration of heavy transition metal WSMs into functional devices. In this work, we present a chemical vapor transport (CVT)-based synthesis strategy for high-quality NbP nanosheets and successfully integrate them with a bowtie antenna structure to develop a novel THz detector. The detector operates in a zero-bias mode, leveraging photon-Weyl fermion interactions to achieve high-performance THz detection. It demonstrates a broad detection range from 0.02 to 0.30 THz, an ultrafast response time of 790 ns, a noise equivalent power as low as 6.25 × 10^-11 W Hz^−1/2, and a responsivity of 156 V/W. Furthermore, we achieve heterodyne mixing in the microwave regime with a local oscillator bandwidth exceeding 67 GHz. These findings advance the application of WSMs in optoelectronic detection and provide new insights into the interplay between topological properties and photoresponse mechanisms, paving the way for next-generation THz photonic devices.