Strain-induced circular photogalvanic current in Dirac semimetal Cd3As2 films epitaxied on a GaAs(111)B substrate
Strain-induced circular photogalvanic current in Dirac semimetal Cd3As2 films epitaxied on a GaAs(111)B substrate
复制标题
GaAs (111)B 衬底上外延狄拉克半金属 Cd3As2 薄膜中的应变感应环光生电流
DOI：
10.1039/d1nr05812f
复制
发表时间：
2022-01-07
期刊：
影响因子：
6.7
通讯作者：
Zhang, Xinhui
中科院分区：
文献类型：
--
作者：
Liang, Gaoming;Zhai, Guihao;Zhang, Xinhui
狄拉克半金属材料(DSM)Cd_3As_2在探索新的量子现象和高速光电子应用方面受到了极大的关注。从理论上预测了在理想狄拉克系统中，由于在狄拉克点附近的对称光激发，由光激发的自旋取向输运产生的圆形光电流将消失。本文报道了在GaAs(111)B衬底上外延生长的Cd_3As_2薄膜的CPGE光电流的观测结果。CPGE的特征由它在转换光辐射螺旋度时的符号反转以及它对激发入射角度和功率的依赖来证实。通过比较不同厚度薄膜的CPGE响应，认为CPGE是由于经历了较大外延应变的Cd_3As_2薄膜的结构对称性降低和电子能带结构大幅度改变所致。我们的实验结果为DSM中的能带工程和奇异的螺旋度相关的光电流现象提供了有价值的参考，为其潜在的光旋电子器件应用提供了参考。
Dirac semimetal (DSM) Cd3As2 has drawn great attention for exploring the novel quantum phenomena and high-speed optoelectronic applications. The circular photogalvanic effect (CPGE) current, resulting from the optically-excited spin orientation transport, was theoretically predicted to vanish in an ideal Dirac system due to the symmetric photoexcitation about the Dirac point. Here, we reported the observation of the CPGE photocurrent in epitaxial Cd3As2 thin films grown on a GaAs(111)B substrate. The signature of the CPGE is confirmed by its sign reversal upon switching the helicity of optical radiation, as well as its dependence on the excitation incident angle and power. By comparison of the CPGE response between the films with different thicknesses, it is suggested that the observed CPGE results from the reduced structure symmetry and substantially modified electronic band structure of the Cd3As2 thin film that undergoes large epitaxial strain. Our experimental findings provide a valuable reference for the band engineering and exotic helicity-dependent photocurrent phenomena in DSMs towards their potential opto-spintronic device applications.