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arXiv · 2010.00877

Relaxation dynamics of the optically driven nonequilibrium states in the electron- and hole-doped topological-insulator materials $(Bi_{1-x}Sb_{x})_{2}Te_{3}$

Chris Reinhoffer·Yu Mukai·Semyon Germanskiy·Andrea Bliesener·Gertjan Lippertz·Anjana Uday·A. A. Taskin·Yoichi Ando·Zhe Wang·Paul H. M. van Loosdrecht
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Abstract

We report on time-resolved mid-infrared-pump terahertz-transmission-probe studies of the topological-insulator materials $(Bi_{1-x}Sb_{x})_{2}Te_{3}$, 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 bandgap, which are selectively excited by changing the pump-pulse energy. For the below-bandgap 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-bandgap excitation is characterized by a compressed exponential decay and nonlinear fluence dependence at high pump flunences, which reflects interaction of the excited nonequilibrium states.

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Chris Reinhoffer, Yu Mukai, Semyon Germanskiy, Andrea Bliesener, Gertjan Lippertz, Anjana Uday, A. A. Taskin, Yoichi Ando, Zhe Wang, Paul H. M. van Loosdrecht. 2020-12-08. Relaxation dynamics of the optically driven nonequilibrium states in the electron- and hole-doped topological-insulator materials $(Bi_{1-x}Sb_{x})_{2}Te_{3}$. https://doi.org/10.1103/physrevmaterials.4.124201

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