Topological insulators (TIs) characterized by gapless and spin-polarized conical band dispersion on their surfaces have been extensively studied over the last decade. This article reviews our recent works on ultrafast carrier dynamics of Sb₂Te₃-based nonmagnetic and magnetic TIs by utilizing state-of-the-art femtosecond time- and angle-resolved photoelectron spectroscopy. We have demonstrated that the electronic recovery time elongated from a few ps to $>$400 ps in case that the Dirac point was close to the Fermi energy in the series of (${\mathrm{Sb}}_{1-x}$${\mathrm{Bi}}_x$)₂Te₃. We also investigated how the magnetic-impurity affects the carrier dynamics in ferromagnetic ${\mathrm{Sb}}_{2-y}$${\mathrm{V}}_y$Te₃. It was found that the electronic recovery time drastically shortened from a few ps to $<$500 fs with increasing vanadium concentration. Since the lifetime of the nonequilibrated surface Dirac fermions can range from femto- to nano-second, Sb₂Te₃-based TIs would be promising for ultrafast spin switching and spin-polarized current generation device applications.

在过去的十年中，已经广泛研究了以表面无间隙和自旋极化锥形带色散为特征的拓扑绝缘体 (TI)。本文回顾了我们最近利用最先进的飞秒时间和角度分辨光电子能谱在基于Sb ₂ Te ₃的非磁性和磁性 TI 的超快载流子动力学方面的工作。我们已经证明电子恢复时间从几 ps 延长到$>$400 ps，以防狄拉克点在 (${\mathrm{锑}}_{1——X}$${\mathrm{双}}_X$) ₂特₃ . 我们还研究了磁性杂质如何影响铁磁中的载流子动力学${\mathrm{锑}}_{2——是}$${\mathrm{伏}}_{是}$特₃。发现电子恢复时间从几 ps 急剧缩短到$<$500 fs 随着钒浓度的增加。由于非平衡表面狄拉克费米子的寿命可以从飞秒到纳秒不等，基于Sb ₂ Te ₃的 TI 将有望用于超快自旋切换和自旋极化电流生成设备应用。