Plasma-Wave Terahertz Detection Mediated by Topological Insulators Surface States

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• 作者：Leonardo Viti ; Dominique Coquillat ; Antonio Politano ; Konstantin A. Kokh ; Ziya S. Aliev ; Mahammad B. Babanly ; Oleg E. Tereshchenko ; Wojciech Knap ; Evgueni V. Chulkov ; Miriam S. Vitiello
• 刊名：Nano Letters
• 出版年：2016
• 出版时间：January 13, 2016
• 年：2016
• 卷：16
• 期：1
• 页码：80-87
• 全文大小：501K
• ISSN：1530-6992

文摘

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)Se_x stoichiometry, and by gating the surface of nanoscale field-effect-transistors, exploiting thin flakes of Bi₂Te_2.2Se_0.8 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 Bi₂Te_2.2Se_0.8 flake. The reported detection performances allow a realistic exploitation of TSS for large-area, fast imaging, promising superb impacts on THz photonics.