Terahertz emission from layered GaTe crystal due to surface lattice reorganization and in-plane noncubic mobility anisotropy
Terahertz emission from layered GaTe crystal due to surface lattice reorganization and in-plane noncubic mobility anisotropy
复制标题
由于表面晶格重组和面内非立方迁移率各向异性，层状 GaTe 晶体的太赫兹发射
DOI：
10.1364/prj.7.000518
复制
发表时间：
2019-05-01
影响因子：
7.6
通讯作者：
Jie, Wanqi
中科院分区：
文献类型：
--
作者：
Dong, Jiangpeng;Gradwohl, Kevin-P.;Jie, Wanqi
In this work, a model based on the optical rectification effect and the photocurrent surge effect is proposed to describe the terahertz emission mechanism of the layered GaTe crystal. As a centrosymmetric crystal, the optical rectification effect arises from the breaking of the inversion symmetry due to lattice reorganization of the crystal’s surface layer. In addition, the photocurrent surge originating from the unidirectional charge carrier diffusion—due to the noncubic mobility anisotropy within the layers—produces terahertz radiation. This is confirmed by both terahertz emission spectroscopy and electric property characterization. The current surge perpendicular to the layers also makes an important contribution to the terahertz radiation, which is consistent with its incident angle dependence. Based on our results, we infer that the contribution of optical rectification changes from 90% under normal incidence to 23% under a 40° incidence angle. The results not only demonstrate the terahertz radiation properties of layered GaTe bulk crystals, but also promise the potential application of terahertz emission spectroscopy for characterizing the surface properties of layered materials.
