Antiferromagnetic semimetal terahertz photodetectors enhanced through weak localization
Dong Wang, Liu Yang, Zhen Hu, Fang Wang, Yage Yang, Xiaokai Pan, Zhuo Dong, Shijian Tian, Libo Zhang, Han Li, Mengjie Jiang, Keqin Tang, Fuxing Dai, Kai Zhang, Wei Lü, Xiaoshuang Chen, Lin Wang, Weida Hu
Abstract
Effective detection is critical for terahertz applications, yet it remains hindered by the unclear mechanisms that necessitate a deeper understanding of photosensitive materials with exotic physical phenomena. Here, we investigate the terahertz detection capabilities of the two-dimensional antiferromagnetic semimetal NbFeTe2. Our study reveals that the interaction between antiferromagnetic magnetic moments and electron spin induces disordered carriers to hop between localized states, resulting in a nonlinear increase in responsivity as temperature decreases. We integrate asymmetric electrodes to generate a sufficient Seebeck potential, enabling carriers to overcome the barrier of localized states and achieve reordering at room temperature. Additionally, the self-powered performance of the NbFeTe₂/graphene heterojunction is optimized by the built-in electric field, achieving peak responsivity of 220 V W-1 and noise equivalent power of <20 pW Hz-1/2. These results shed light on the potential of antiferromagnetic semimetals in large-area, high-speed imaging applications, marking a significant advancement in terahertz photonics. This study reveals that the interaction between antiferromagnetic magnetic moments and electron spin causes disordered carriers to hop between localized states, resulting in a nonlinear increase in the terahertz responsivity as temperature decreases.