Optical Conductivity of Bismuth-Based Topological Insulators
Abstract
The optical conductivity σ1(ω) and the spectral weight SW of four topological insulators with increasing chemical compensation (Bi2Se3,Bi2Se2Te,Bi2-xCaxSe3, and Bi2Te2Se) have been measured from 5 to 300 K and from subterahertz to visible frequencies. The effect of compensation is clearly observed in the infrared spectra through the suppression of an extrinsic Drude term and the appearance of strong absorption peaks that we assign to electronic transitions among localized states. From the far-infrared spectral weight SW of the most compensated sample (Bi2Te2Se), one can estimate a density of charge carriers on the order of 1017/cm3 in good agreement with transport data. Those results demonstrate that the low-energy electrodynamics in single crystals of topological insulators, even at the highest degree of compensation presently achieved, is still influenced by three-dimensional charge excitations.
Recommended Citation
P. P. Di et al., "Optical Conductivity of Bismuth-Based Topological Insulators," Physical review B: Condensed matter and materials physics, vol. 86, no. 4, American Physical Society (APS), Jul 2012.
The definitive version is available at https://doi.org/10.1103/PhysRevB.86.045439
Department(s)
Physics
International Standard Serial Number (ISSN)
1098-0121
Document Type
Article - Journal
Document Version
Final Version
File Type
text
Language(s)
English
Rights
© 2012 American Physical Society (APS), All rights reserved.
Publication Date
01 Jul 2012
