Mid-infrared transient reflectance study of the Dirac semimetal Cd3As2 under strong optical pumping
Mid-infrared transient reflectance study of the Dirac semimetal Cd3As2 under strong optical pumping
复制标题
强光泵浦下狄拉克半金属Cd3As2的中红外瞬态反射率研究
DOI：
10.1103/physrevb.101.174310
复制
发表时间：
2020
影响因子：
3.7
通讯作者：
Zhang Xinhui
中科院分区：
文献类型：
--
作者：
Zhai Guihao;Ma Chaoyang;Xiang Junsen;Ye Jialiang;Li Ting;Li Ying;Sun Peijie;Chen Genfu;Wu Xiaoguang;Zhang Xinhui
三维狄拉克半金属最近因其奇异的性质而引起了人们的广泛关注。了解热载流子激发及其随后的弛豫是在红外 (IR) 和太赫兹 (THz) 频率范围内发挥功能的光电器件的先决条件。在这项工作中，通过在室温下强光泵浦下使用时间分辨泵浦探针反射率（）测量来探索中红外块状单晶的光激发热载流子动力学。通过结合实验结果和理论模型，我们分析了强光激发下的瞬态热载流子重新分布以及随后的带间跃迁。我们表明，由于狄拉克带之间的转变以及涉及狄拉克带和非狄拉克带的转变的相互作用， 的响应具有复杂的行为。在整个中红外区域测量中，我们发现这主要是由折射率的变化造成的，而不是消光系数的变化。我们的研究结果有助于理解强光泵浦下的瞬态热电子激发和弛豫，并为基于此的超快光电子应用提供有价值的参考。
The three-dimensional Dirac semimetalhas attracted intensive attention recently for its exotic properties. Understanding the hot carrier excitation and its subsequent relaxation is a prerequisite for-based optoelectronics functional in the infrared (IR) and terahertz (THz) frequency range. In this work, the photoexcited hot carrier dynamics of a bulk single crystalin the mid-IR has been explored by using the time-resolved pump-probe reflectance () measurement at room temperature under a strong optical pumping. By combining the experimentalresults and theoretical modeling, we analyzed the transient hot carrier redistribution upon a strong photoexcitation and the subsequent interband transitions. We show that theresponse ofhas a complex behavior, due to the interplay of transitions between Dirac bands and transitions involving both the Dirac and non-Dirac bands. Throughout the mid-IR region measured, we find thatis contributed primarily by changes in the refractive index, rather than by changes in the extinction coefficient. Our findings can help understanding the transient hot electron excitation and relaxation inunder an intense optical pumping, and provide a valuable reference for the-based ultrafast optoelectronics application.