Plasma-Wave Terahertz Detection Mediated by Topological Insulators Surface States

Abstract

Topological insulators (TIs) represent a novel quantum state of matter, characterized by edge or surface-states, showing up on the topological character of the bulk wave functions. Allowing electrons to move along their surface, but not through their inside, they emerged as an intriguing material platform for the exploration of exotic physical phenomena, somehow resembling the graphene Dirac-cone physics, as well as for exciting applications in optoelectronics, spintronics, nanoscience, low-power electronics, and quantum computing. Investigation of topological surface states (TSS) is conventionally hindered by the fact that in most of experimental conditions the TSS properties are mixed up with those of bulk-states. Here, we activate, probe, and exploit the collective electronic excitation of TSS in the Dirac cone. By engineering Bi2Te(3-x)Sex stoichiometry, and by gating the surface of nanoscale field-effect-transistors, exploiting thin flakes of Bi2Te2.2Se0.8 or Bi2Se3, we provide the first demonstration of room-temperature terahertz (THz) detection mediated by overdamped plasma-wave oscillations on the "activated" TSS of a Bi2Te2.2Se0.8 flake. The reported detection performances allow a realistic exploitation of TSS for large-area, fast imaging, promising superb impacts on THz photonics.

Optoelectronic devices, plasmonics, and photonics with topological insulators

“…In such a regime, the dc photoresponse is characterized by peaks at the odd multiples of the lowest plasma-wave frequency. For typical device lengths and carrier densities, the fundamental frequency of plasma waves is in the terahertz (THz) range, so that photodetectors based on the resonant collective density oscillations 62,65,67 can be engineered to operate at THz frequencies.…”

A Plasmonic Monopole Antenna Array on Flexible Photovoltaic Panels for Further Use of the Green Energy Harvesting

“…These measurements are performed at 900 MHz, because such a signal is the most available one in the space due to the GSM mobile communication network [25]. Nevertheless, the proposed antenna array shows a plasmonic resonance at 900 MHz, in which the mutual coupling effects decay significantly [7].…”

“…Nevertheless, such a technology led to design efficient Terahertz detectors with a thermoelectric response [6]. Such phenomena can be characterized by edge or surface-states, i.e., the electrons move along the surface of plasmonic structures instead of their inside [7]. Moreover, these plasmonic structures have been applied recently in wireless communication systems.…”

Dual-Polarized Multi-Band Infrared Energy Harvesting Using H-Shaped Metasurface Absorber

“…An optical rectenna consists of a nano antenna to capture solar radiation and a rectifier, Metal Insulator Metal (MIM) diode [8], to convert the captured energy to useful DC power. The recent advancements in nanotechnology enabled the possibility to fabricate optical antennas and other terahertz devices [9][10][11] with a broad range of potential applications [12][13][14][15][16]. The fact that optical rectennas can capture solar energy during the day and night with wideband reception and higher theoretical conversion efficiency make them advantageous over photovoltaic technology.…”