Observation of the universal magnetoelectric effect in a 3D topological insulator
| Autor: | Dziom, V., Shuvaev, A., Pimenov, A., Astakhov, G. V., Ames, C., Bendias, K., Böttcher, J., Tkachov, G., Hankiewicz, E. M., Brüne, C., Buhmann, H, Molenkamp, L. W. |
|---|---|
| Rok vydání: | 2016 |
| Předmět: | |
| Zdroj: | Nat. Commun. 8, 15197 (2017) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1038/ncomms15197 |
| Popis: | The electrodynamics of topological insulators (TIs) is described by modified Maxwell's equations, which contain additional terms that couple an electric field to a magnetization and a magnetic field to a polarization of the medium, such that the coupling coefficient is quantized in odd multiples of $e^2 / 2 h c $ per surface. Here, we report on the observation of this so-called topological magnetoelectric (TME) effect. We use monochromatic terahertz (THz) spectroscopy of TI structures equipped with a semi-transparent gate to selectively address surface states. In high external magnetic fields, we observe a universal Faraday rotation angle equal to the fine structure constant $\alpha = e^2 / \hbar c$ when a linearly polarized THz radiation of a certain frequency passes through the two surfaces of a strained HgTe 3D TI. These experiments give insight into axion electrodynamics of TIs and may potentially be used for a metrological definition of the three basic physical constants. Comment: Submitted 13 March, 2016; 7 pages, 4 figures |
| Databáze: | arXiv |
| Externí odkaz: |
|