Observation of Floquet-Bloch states on the surface of a topological insulator
| Autor: | Wang, Y. H., Steinberg, H., Jarillo-Herrero, P., Gedik, N. |
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| Rok vydání: | 2013 |
| Předmět: | |
| Zdroj: | Science,342,453 (2013) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1126/science.1239834 |
| Popis: | The unique electronic properties of the surface electrons in a topological insulator are protected by time-reversal symmetry. Circularly polarized light naturally breaks time-reversal symmetry, which may lead to an exotic surface quantum Hall state. Using time- and angle-resolved photoemission spectroscopy, we show that an intense ultrashort mid-infrared pulse with energy below the bulk band gap hybridizes with the surface Dirac fermions of a topological insulator to form Floquet-Bloch bands. These photon dressed surface bands exhibit polarization-dependent band gaps at avoided crossings. Circularly polarized photons induce an additional gap at the Dirac point, which is a signature of broken time-reversal symmetry on the surface. These observations establish the Floquet-Bloch bands in solids and pave the way for optical manipulation of topological quantum states of matter. Comment: 23 pages including supplementary materials |
| Databáze: | arXiv |
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