The discovery of Dirac semimetal has stimulated bourgeoning interests for exploring exotic quantum-transport phenomena, holding great promise for manipulating the performance of photoelectric devices that are related to nontrivial band topology. Nevertheless, it still remains elusive on both the device implementation and immediate results, with some enhanced or technically applicable electronic properties signified by the Dirac fermiology. By means of Pt doping, a type-II Dirac semimetal Ir_1–xPt_xTe₂ with protected crystal structure and tunable Fermi level has been achieved in this work. It has been envisioned that the metal–semimetal–metal device exhibits an order of magnitude performance improvement at terahertz frequency when the Fermi level is aligned with the Dirac node (i.e., x ∼ 0.3) and a room-temperature photoresponsivity of 0.52 A·W^–1 at 0.12 THz and 0.45 A·W^–1 at 0.3 THz, which benefited from the excitation of type-II Dirac fermions. Furthermore, van der Waals integration with Dirac semimetals exhibits superb performance with noise equivalent power less than 24 pW·Hz^–0.5, rivaling the state-of-the-art detectors. Our work provides a route to explore the nontrivial topology of Dirac semimetal for addressing targeted applications in imaging and biomedical sensing across a terahertz gap.

中文翻译：

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室温下巨大的太赫兹光响应：II型狄拉克铁电学的标志

狄拉克（Dirac）半金属的发现激发了探索新兴的量子传输现象的新兴兴趣，为操纵与非平凡的频带拓扑相关的光电器件的性能提供了广阔的前景。然而，它在设备实现和即时结果方面仍然难以捉摸，狄拉克铁电学已表明其具有某些增强的或在技术上适用的电子特性。通过Pt掺杂，II型Dirac半金属Ir _{1– x} Pt _x Te ₂这项工作已经实现了具有受保护的晶体结构和可调节的费米能级。已经设想的是，金属-半金属-金属装置具有在太赫频率的数量级的性能改进的顺序时，费米能级与狄拉克节点（对准即，X〜0.3）和0.52 A的室温光响应·W ^-1 0.12赫兹和0.45 A·W ^-1在0.3赫兹，它从II型狄拉克费米子的激励受益。此外，范德华与Dirac半金属的结合表现出卓越的性能，其等效噪声功率小于24 pW·Hz ^–0.5与最先进的探测器相媲美。我们的工作为探索狄拉克半金属的非平凡拓扑提供了一条途径，以解决跨太赫兹间隙的成像和生物医学传感领域的目标应用。