Relaxation dynamics of the optically driven nonequilibrium states in the electron- and hole-doped topological-insulator materials (Bi1−xSbx)2Te3
| Autor: | Gertjan Lippertz, Yoichi Ando, Paul H. M. van Loosdrecht, Zhe Wang, Chris Reinhoffer, Semyon Germanskiy, Andrea Bliesener, Anjana Uday, A. A. Taskin, Yu Mukai |
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| Rok vydání: | 2020 |
| Předmět: |
Materials science
Physics and Astronomy (miscellaneous) Band gap Relaxation (NMR) 02 engineering and technology 021001 nanoscience & nanotechnology 01 natural sciences Topological insulator Excited state 0103 physical sciences General Materials Science Charge carrier Exponential decay Atomic physics 010306 general physics 0210 nano-technology Energy (signal processing) Excitation |
| Zdroj: | Physical Review Materials. 4 |
| ISSN: | 2475-9953 |
| Popis: | We report on time-resolved mid-infrared-pump terahertz-transmission-probe studies of the topological-insulator materials ${({\mathrm{Bi}}_{1\ensuremath{-}x}{\mathrm{Sb}}_{x})}_{2}{\mathrm{Te}}_{3}$, in which by varying $x$ charge carriers are chemically tuned to be of $n$-type or $p$-type. Relaxation dynamics is found to be different in various aspects for transitions below or above the band gap, which are selectively excited by changing the pump-pulse energy. For the below-band-gap excitation, an exponential decay of the pump-probe signals is observed, which exhibits linear dependence on the pump-pulse fluence. In contrast, the relaxation dynamics for the above-band-gap excitation is characterized by a compressed exponential decay and nonlinear fluence dependence at high pump flunences, which reflects interaction of the excited nonequilibrium states. |
| Databáze: | OpenAIRE |
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