Manifestation of Kinetic Inductance in Terahertz Plasmon Resonances in Thin-Film Cd₃As₂

Abstract

Three-dimensional (3D) semimetals have been predicted and demonstrated to have a wide variety of interesting properties associated with its linear energy dispersion. In analogy to twodimensional (2D) Dirac semimetals, such as graphene, Cd3As2, a 3D semimetal, has shown ultrahigh mobility, large Fermi velocity, and has been hypothesized to support plasmons at terahertz frequencies. In this work, we demonstrate synthesis of high-quality large-area Cd3As2 thin-films through thermal evaporation as well as the experimental realization of plasmonic structures consisting of periodic arrays of Cd3As2 stripes. These arrays exhibit sharp resonances at terahertz frequencies with associated quality-factors (Q) as high as ~ 3.7. Such spectrally-narrow resonances can be understood on the basis of a large kinetic-inductance, resulting from a long momentum scattering time, which in our films can approach ~1 ps at room-temperature.Moreover, we demonstrate an ultrafast tunable response through excitation of photo-induced 2 carriers in optical pump / terahertz probe experiments. Our results evidence that the intrinsic 3D nature of Cd3As2 provides for a very robust platform for terahertz plasmonic applications. Overall, our observations pave a way for the development of myriad terahertz (opto) electronic devices based on Cd3As2 and other 3D Dirac semimetals, benefiting from strong coupling of terahertz radiation, ultrafast transient response, magneto-plasmon properties, etc. Moreover, the long momentum scattering time, thus large kinetic inductance in Cd3As2, also holds enormous potential for the re-design of passive elements such as inductors and hence can have a profound impact in the field of RF integrated circuits.

Quantum oscillations in Dirac magnetoplasmons

“…With first experiments on three-dimensional Dirac plasmons appearing recently [27][28][29][30][31][32], the results of this paper should be accessible in current experiments. Going forward, the dependence on the magnetic field provides a novel way to tailor the Dirac plasmon frequency.…”

“…Our main focus are three-dimensional gapless Dirac semimetals, for which the single-particle dispersion is a linear function of momentum. For these systems, the theoretical study of plasmons is a flourishing subfield [13][14][15][16][17][18][19][20][21][22][23][24][25][26], and first measurements of plasmons have recently been reported in optical studies [27][28][29][30][31] and electron-loss spectroscopy [32].…”

Up‐And‐Coming Advances in Optical and Microwave Nonreciprocity: From Classical to Quantum Realm

“…The existence of such defined helicity charge unites the Weyl points with helicity‐degenerate valleys in 2D transition metal dichalcogenides (TMDCs), which recently emerged as a versatile platform for valleytronics. [ 149 ] The superior properties of WSs in microwave and THz frequency ranges, including relatively low loss caused by a large momentum scattering time ≈1 ps at room temperature, [ 150 ] epsilon‐near‐zero and hyperbolic regime, make them very promising for electronic and optoelectronic applications.…”

Spatiotemporal Terahertz Metasurfaces for Ultrafast All‐Optical Switching with Electric‐Triggered Bistability

“…[ 17–22 ] Hybridizing metasurfaces with active natural materials has led to exceptional opportunities in real‐time THz functional devices, and significant progresses have been obtained in the THz spatiotemporal manipulations. [ 1,23–25 ] In the last decade, there has been a growing interest in actualizing the multidimensional modulation in THz metadevices by implementing mechanical, [ 26–30 ] electrical, [ 31–42 ] thermal, [ 43–46 ] and optical [ 47–62 ] approaches. Among them, the contact‐free all‐optical means has gained a fast appreciation by taking full advantage of high‐speed modulation and switching, whose figure of merits depend on ultrafast semiconductor relaxations to a large extent.…”

“…Among them, the contact‐free all‐optical means has gained a fast appreciation by taking full advantage of high‐speed modulation and switching, whose figure of merits depend on ultrafast semiconductor relaxations to a large extent. [ 63 ] Considering the rapid emergence of different photophysics, scientists and researchers continuously pursue numerous photoactive materials to tailor THz waves, which embrace the traditional semiconductors, [ 47,50,51,64–67 ] superconductors, [ 68 ] perovskites, [ 52,54 ] Weyl semimetals, [ 48 ] topological insulators, [ 56 ] and transition metal dichalcogenides. [ 57,69 ] However, these materials suffer from a single functionality in terms of switching one resonant state with ultrafast temporal evolution, owing to the spatially unchangeable nature of metasurfaces.…”