Please use this identifier to cite or link to this item: https://hdl.handle.net/10356/100919
Title: Terahertz conductivity of topological surface states in Bi1.5Sb0.5Te1.8Se1.2
Authors: Tang, Chi Sin
Xia, Bin
Zou, Xingquan
Chen, Shi
Ou, Hong-Wei
Wang, Lan
Rusydi, A.
Zhu, Jian-Xin
Chia, Elbert E. M.
Keywords: DRNTU::Science::Chemistry::Biochemistry::Spectroscopy
Issue Date: 2013
Source: Tang, C. S., Xia, B., Zou, X., Chen, S., Ou, H.-W., Wang, L., et al. (2013). Terahertz conductivity of topological surface states in Bi1.5Sb0.5Te1.8Se1.2. Scientific Reports, 3, 3513.
Series/Report no.: Scientific reports
Abstract: Topological insulators are electronic materials with an insulating bulk and conducting surface. However, due to free carriers in the bulk, the properties of the metallic surface are difficult to detect and characterize in most topological insulator materials. Recently, a new topological insulator Bi1.5Sb0.5Te1.7Se1.3 (BSTS) was found, showing high bulk resistivities of 1–10 Ω.cm and greater contrast between the bulk and surface resistivities compared to other Bi-based topological insulators. Using Terahertz Time-Domain Spectroscopy (THz-TDS), we present complex conductivity of BSTS single crystals, disentangling the surface and bulk contributions. We find that the Drude spectral weight is 1–2 orders of magnitude smaller than in other Bi-based topological insulators, and similar to that of Bi2Se3 thin films, suggesting a significant contribution of the topological surface states to the conductivity of the BSTS sample. Moreover, an impurity band is present about 30 meV below the Fermi level, and the surface and bulk carrier densities agree with those obtained from transport data. Furthermore, from the surface Drude contribution, we obtain a ~98% transmission through one surface layer — this is consistent with the transmission through single-layer or bilayer graphene, which shares a common Dirac-cone feature in the band structure.
URI: https://hdl.handle.net/10356/100919
http://hdl.handle.net/10220/18597
ISSN: 2045-2322
DOI: 10.1038/srep03513
Rights: © 2013 The Author(s) (Nature Publishing Group) This paper was published in Scientific Reports and is made available as an electronic reprint (preprint) with permission of The Author(s). The paper can be found at the following official DOI: doi:http://dx.doi.org/10.1038/srep03513.  One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper is prohibited and is subject to penalties under law.
Fulltext Permission: open
Fulltext Availability: With Fulltext
Appears in Collections:SPMS Journal Articles

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