Emergent topological Dirac semimetals afford fresh pathways for optoelectronics, although device implementation has been elusive to date. Specifically, palladium ditelluride (PdTe₂) combines the capabilities provided by its peculiar band structure, with topologically protected electronic states, with advantages related to the occurrence of high-mobility charge carriers and ambient stability. Here, we demonstrate large photogalvanic effects with high anisotropy at terahertz frequency in PdTe₂-based devices. A responsivity of 10 A/W and a noise-equivalent power lower than 2 pW/Hz^0.5 are achieved at room temperature, validating the suitability of PdTe₂-based devices for applications in photosensing, polarization-sensitive detection, and large-area fast imaging. Our findings open opportunities for exploring uncooled and sensitive photoelectronic devices based on topological semimetals, especially in the highly pursuit terahertz band.

新兴的狄拉克拓扑半金属为光电子学提供了新的途径，尽管迄今为止设备的实现还难以捉摸。具体而言，二碲化钯（PdTe ₂）结合了其独特的能带结构所提供的功能以及受拓扑保护的电子态，并具有与出现高迁移率电荷载流子和环境稳定性相关的优势。在这里，我们展示了在基于PdTe ₂的设备中以太赫兹频率具有高各向异性的大光电流效应。在室温下可实现10 A / W的响应度和低于2 pW / Hz的等效噪声功率^0.5，从而验证了PdTe ₂的适用性应用于光敏，偏振敏感检测和大面积快速成像的设备。我们的发现为探索基于拓扑半金属的未冷却且灵敏的光电器件提供了机会，尤其是在高度追求的太赫兹波段中。