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|Title:||Topological-insulator-based terahertz modulator||Authors:||Wang, X. B.
Zhu, D. P.
Chia, Elbert Ee Min
|Issue Date:||2017||Source:||Wang, X. B., Cheng, L., Wu, Y., Zhu, D. P., Wang, L., Zhu, J.-X., . . . Chia, E. E. M. (2017). Topological-insulator-based terahertz modulator. Scientific Reports, 7, 13486-. doi:10.1038/s41598-017-13701-9||Series/Report no.:||Scientific Reports||Abstract:||Three dimensional topological insulators, as a new phase of quantum matters, are characterized by an insulating gap in the bulk and a metallic state on the surface. Particularly, most of the topological insulators have narrow band gaps, and hence have promising applications in the area of terahertz optoelectronics. In this work, we experimentally demonstrate an electronically-tunable terahertz intensity modulator based on Bi1:5Sb0:5Te1:8Se1:2 single crystal, one of the most insulating topological insulators. A relative frequency-independent modulation depth of ~62% over a wide frequency range from 0.3 to 1.4 THz has been achieved at room temperature, by applying a bias current of 100 mA. The modulation in the low current regime can be further enhanced at low temperature. We propose that the extraordinarily large modulation is a consequence of thermally-activated carrier absorption in the semiconducting bulk states. Our work provides a new application of topological insulators for terahertz technology.||URI:||https://hdl.handle.net/10356/88274
|ISSN:||2045-2322||DOI:||http://dx.doi.org/10.1038/s41598-017-13701-9||Rights:||© 2017 The Author(s). This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. Te images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.||metadata.item.grantfulltext:||open||metadata.item.fulltext:||With Fulltext|
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