Anomalous behavior of the $E_u^1$ infrared-active phonon mode in a Bi$_{2-x}$Sr$_x$Se$_3$ crystal
| Autor: | Melnikov, A. A., Boldyrev, K. N., Selivanov, Yu. G., Chekalin, S. V. |
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| Rok vydání: | 2022 |
| Předmět: | |
| Zdroj: | JETP Letters (2021) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1134/S0021364022010039 |
| Popis: | We have studied spectral evolution of the $E_u^1$ phonon line of a topological insulator Bi$_{2-x}$Sr$_x$Se$_3$ with temperature. Unlike the Raman-active phonons, the $E_u^1$ mode demonstrates softening upon cooling the crystal, and the corresponding spectral line acquires a pronounced Fano-like shape at temperatures $T\lesssim100$ K. We interpret the latter effect as a signature of specific coupling of the bulk infrared active phonons to surface Dirac electrons. Using coherent resonant excitation of the $E_u^1$ mode as a surface sensitive tool, we have detected softening of the surface counterpart of the bulk $E_u^1$ phonon mode upon strontium doping. This observation can be an evidence of enhanced electron-phonon interaction at the surface of the Bi$_{2-x}$Sr$_x$Se$_3$ crystal. Comment: 6 pages, 4 figures |
| Databáze: | arXiv |
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