Wedge Dyakonov Waves and Dyakonov Plasmons in Topological Insulator Bi2Se3 Probed by Electron Beams
| Autor: | Klaus Kern, Peter A. van Aken, Cigdem Ozsoy-Keskinbora, Nahid Talebi, Hadj M. Benia, Christoph Koch |
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| Rok vydání: | 2016 |
| Předmět: |
Physics
Condensed matter physics Band gap General Engineering General Physics and Astronomy 02 engineering and technology Electron 021001 nanoscience & nanotechnology 01 natural sciences 7. Clean energy Wedge (geometry) Topological insulator Excited state 0103 physical sciences Density of states General Materials Science Atomic physics 010306 general physics 0210 nano-technology Fermi gas Plasmon |
| Zdroj: | ACS nano. 10(7) |
| ISSN: | 1936-086X |
| Popis: | Bi2Se3 has recently attracted a lot of attention because it has been reported to be a platform for the realization of three-dimensional topological insulators. Due to this exotic characteristic, it supports excitations of a two-dimensional electron gas at the surface and, hence, formation of Dirac-plasmons. In addition, at higher energies above its bandgap, Bi2Se3 is characterized by a naturally hyperbolic electromagnetic response, with an interesting interplay between type-I and type-II hyperbolic behaviors. However, still not all the optical modes of Bi2Se3 have been explored. Here, using mainly electron energy-loss spectroscopy and corresponding theoretical modeling we investigate the full photonic density of states that Bi2Se3 sustains, in the energy range of 0.8 eV-5 eV. We show that at energies below 1 eV, this material can also support wedge Dyakonov waves. Furthermore, at higher energies a huge photonic density of states is excited in structures such as waveguides and resonators made of Bi2Se3 due to the hyperbolic dispersion. |
| Databáze: | OpenAIRE |
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