Relaxation dynamics of the optically driven nonequilibrium states in the electron- and hole-doped topological-insulator materials $(B{i}_{1-x}S{b}_x{)}_{2}T{e}_3$

Abstract

We report on time-resolved mid-infrared-pump terahertz-transmission-probe studies of the topological-insulator materials $(B{i}_{1-x}S{b}_x{)}_{2}T{e}_3$, 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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Cited by in corpus (4)

• Van der Waals engineering of ultrafast carrier dynamics in magnetic heterostructures
• Ultrafast dynamics of optically excited charge carriers in the room-temperature antiferromagnetic semiconductor $\alpha$-MnTe
• Anomalous electronic energy relaxation and soft phonons in the Dirac semimetal Cd${}_3$As${}_2$
• Research on topological materials using ultrafast spectroscopy