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Title: Optical conductivity of topological insulator thin films

Abstract

We present a detailed theoretical study on the optoelectronic properties of topological insulator thin film (TITFs). The k·p approach is employed to calculate the energy spectra and wave functions for both the bulk and surface states in the TITF. With these obtained results, the optical conductivities induced by different electronic transitions among the bulk and surface states are evaluated using the energy-balance equation derived from the Boltzmann equation. We find that for Bi{sub 2}Se{sub 3}-based TITFs, three characteristic regimes for the optical absorption can be observed. (i) In the low radiation frequency regime (photon energy ℏω<200 meV), the free-carrier absorption takes place due to intraband electronic transitions. An optical absorption window can be observed. (ii) In the intermediate radiation frequency regime (200300 meV), the optical absorption can be achieved via interband electronic transitions from bulk and surface states in the valance band to bulk and surface states in the conduction band. A strong absorption peak can be observed. These interesting findings indicate that optical measurements can be applied to identify the energy regimes of bulk and surface states in the TITF.

Authors:
 [1];  [1];  [2];  [3]
  1. Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031 (China)
  2. (China)
  3. Department of Physics, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerpen (Belgium)
Publication Date:
OSTI Identifier:
22403010
Resource Type:
Journal Article
Journal Name:
Journal of Applied Physics
Additional Journal Information:
Journal Volume: 117; Journal Issue: 17; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0021-8979
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ABSORPTION; BISMUTH SELENIDES; BOLTZMANN EQUATION; ELECTRONIC STRUCTURE; ENERGY SPECTRA; OPACITY; PHOTONS; SURFACES; THIN FILMS; TOPOLOGY

Citation Formats

Li, L. L., E-mail: lllihfcas@foxmail.com, Xu, W., Department of Physics, Yunnan University, Kunming 650091, and Peeters, F. M. Optical conductivity of topological insulator thin films. United States: N. p., 2015. Web. doi:10.1063/1.4919429.
Li, L. L., E-mail: lllihfcas@foxmail.com, Xu, W., Department of Physics, Yunnan University, Kunming 650091, & Peeters, F. M. Optical conductivity of topological insulator thin films. United States. doi:10.1063/1.4919429.
Li, L. L., E-mail: lllihfcas@foxmail.com, Xu, W., Department of Physics, Yunnan University, Kunming 650091, and Peeters, F. M. Thu . "Optical conductivity of topological insulator thin films". United States. doi:10.1063/1.4919429.
@article{osti_22403010,
title = {Optical conductivity of topological insulator thin films},
author = {Li, L. L., E-mail: lllihfcas@foxmail.com and Xu, W. and Department of Physics, Yunnan University, Kunming 650091 and Peeters, F. M.},
abstractNote = {We present a detailed theoretical study on the optoelectronic properties of topological insulator thin film (TITFs). The k·p approach is employed to calculate the energy spectra and wave functions for both the bulk and surface states in the TITF. With these obtained results, the optical conductivities induced by different electronic transitions among the bulk and surface states are evaluated using the energy-balance equation derived from the Boltzmann equation. We find that for Bi{sub 2}Se{sub 3}-based TITFs, three characteristic regimes for the optical absorption can be observed. (i) In the low radiation frequency regime (photon energy ℏω<200 meV), the free-carrier absorption takes place due to intraband electronic transitions. An optical absorption window can be observed. (ii) In the intermediate radiation frequency regime (200300 meV), the optical absorption can be achieved via interband electronic transitions from bulk and surface states in the valance band to bulk and surface states in the conduction band. A strong absorption peak can be observed. These interesting findings indicate that optical measurements can be applied to identify the energy regimes of bulk and surface states in the TITF.},
doi = {10.1063/1.4919429},
journal = {Journal of Applied Physics},
issn = {0021-8979},
number = 17,
volume = 117,
place = {United States},
year = {2015},
month = {5}
}