论文标题
内在拓扑绝缘子$ \ text {bi} _ {2-x} \ text {sb} _x \ text {se} _3 $揭示的光学反射率揭示
Nanosecond dynamics in intrinsic topological insulator $\text{Bi}_{2-x}\text{Sb}_x\text{Se}_3$ revealed by time-resolved optical reflectivity
论文作者
论文摘要
$ \ text {bi} _2 \ text {se} _3 $是理想的三维拓扑绝缘子，其中可以将化学电位带入带有锑掺杂的散装带隙。在这里，我们利用超快时间分辨的瞬态反射率来表征$ \ text {bi} _ {2-x} \ text {sb} _x _x \ text {se} _3 $ nanoplatelets中的光激发载体衰减。我们报告了散装载体放松时间的大大放缓，以构成$ \ text {bi} _ {2-x} \ text {sb} _x \ text {se} _3 $ nanoplatelets，与$ n $ n $ n $ -n $ type bulk-metalk-metallic $ \ text $ \ text $ \ text $在零泵通量限制中，哪个接近$ 3.3 \ text {ns} $。这种长寿的衰减在不同的通力和锑浓度之间相关，揭示了$ n $ -type $ \ text {bi} _2 \ text {se} _3 $中不存在的独特衰减动力学，即散装载体的慢分子重组。
$\text{Bi}_2\text{Se}_3$ is an ideal three-dimensional topological insulator in which the chemical potential can be brought into the bulk band gap with antimony doping. Here, we utilize ultrafast time-resolved transient reflectivity to characterize the photoexcited carrier decay in $\text{Bi}_{2-x}\text{Sb}_x\text{Se}_3$ nanoplatelets. We report a substantial slowing of the bulk carrier relaxation time in bulk-insulating $\text{Bi}_{2-x}\text{Sb}_x\text{Se}_3$ nanoplatelets as compared to $n$-type bulk-metallic $\text{Bi}_2\text{Se}_3$ at low temperatures, which approaches $3.3 \text{ ns}$ in the zero pump fluence limit. This long-lived decay is correlated across different fluences and antimony concentrations, revealing unique decay dynamics not present in $n$-type $\text{Bi}_2\text{Se}_3$, namely the slow bimolecular recombination of bulk carriers.
