تقرير
Time-resolved terahertz dynamics in thin films of the topological insulator Bi$_{2}$Se$_3$
| العنوان: | Time-resolved terahertz dynamics in thin films of the topological insulator Bi$_{2}$Se$_3$ |
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| المؤلفون: | Aguilar, R. Valdés, Qi, J., Brahlek, M., Bansal, N., Azad, A., Bowlan, J., Oh, S., Taylor, A. J., Prasankumar, R. P., Yarotski, D. A. |
| سنة النشر: | 2014 |
| المجموعة: | Condensed Matter |
| مصطلحات موضوعية: | Condensed Matter - Mesoscale and Nanoscale Physics, Condensed Matter - Strongly Correlated Electrons |
| الوصف: | We use optical pump--THz probe spectroscopy at low temperatures to study the hot carrier response in thin Bi$_2$Se$_3$ films of several thicknesses, allowing us to separate the bulk from the surface transient response. We find that for thinner films the photoexcitation changes the transport scattering rate and reduces the THz conductivity, which relaxes within 10 picoseconds (ps). For thicker films, the conductivity increases upon photoexcitation and scales with increasing both the film thickness and the optical fluence, with a decay time of approximately 5 ps as well as a much higher scattering rate. These different dynamics are attributed to the surface and bulk electrons, respectively, and demonstrate that long-lived mobile surface photo-carriers can be accessed independently below certain film thicknesses for possible optoelectronic applications. Comment: 4+ pages, 3 figures. Submitted |
| نوع الوثيقة: | Working Paper |
| DOI: | 10.1063/1.4905438 |
| URL الوصول: | http://arxiv.org/abs/1410.5666 |
| رقم الأكسشن: | edsarx.1410.5666 |
| قاعدة البيانات: | arXiv |
| DOI: | 10.1063/1.4905438 |
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