Harnessing large kinetic inductance in Cadmium Arsenide (Cd₃As₂) for miniaturized terahertz spiral inductors

The growing demand for high-speed connectivity, driven by the Internet of Things (IoT) and the emergence of 6G technologies, underscores the crucial role of terahertz (THz) frequencies (0.1-10 THz) in powering high-resolution imaging, ultrasensitive sensing, and ultrafast communication. However, translating these capabilities into real-world applications requires the development of electronic and optical components that can reliably operate at THz frequencies. The relatively low inductance of conventional metal-based inductors at micrometre scales has significantly limited their miniaturization and scalability to THz frequencies. In this work, a miniaturized spiral THz inductor is designed using Cadmium Arsenide (Cd₃As₂), a three-dimensional Dirac semimetal with remarkable electrical characteristics, such as low intrinsic losses and high kinetic inductance. For a spiral length of 1600 µm, the proposed inductor achieves a total inductance of 4.6 nH with a kinetic inductance contribution of 2.7 nH by taking advantage of the long momentum scattering time (τ = 157 fs) and low carrier density of Cd₃As₂. Its size is three times smaller than aluminium-based counterparts without sacrificing performance. Our device demonstrates enhanced scalability and, consequently, greater efficiency. These findings enable compact, high-performance on-chip components for integrated circuits, telecommunications, and IoT applications.