Liang Gaoming, Zhai Guihao, Ma Jialin, Wang Hailong, Zhao Jianhua, Wu Xiaoguang, Zhang Xinhui
State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China.
Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China.
Nanomaterials (Basel). 2023 Jun 29;13(13):1979. doi: 10.3390/nano13131979.
Magnetic element doped CdAs Dirac semimetal has attracted great attention for revealing the novel quantum phenomena and infrared opto-electronic applications. In this work, the circular photogalvanic effect (CPGE) was investigated at various temperatures for the Ni-doped CdAs films which were grown on GaAs(111)B substrate by molecular beam epitaxy. The CPGE current generation was found to originate from the structural symmetry breaking induced by the lattice strain and magnetic doping in the Ni-doped CdAs films, similar to that in the undoped ones. However, the CPGE current generated in the Ni-doped CdAs films was approximately two orders of magnitude smaller than that in the undoped one under the same experimental conditions and exhibited a complex temperature variation. While the CPGE current in the undoped film showed a general increase with rising temperature. The greatly reduced CPGE current generation efficiency and its complex variation with temperature in the Ni-doped CdAs films was discussed to result from the efficient capture of photo-generated carriers by the deep-level magnetic impurity bands and enhanced momentum relaxation caused by additional strong impurity scattering when magnetic dopants were introduced.
磁性元素掺杂的CdAs狄拉克半金属因其能揭示新型量子现象和用于红外光电子应用而备受关注。在这项工作中，通过分子束外延在GaAs(111)B衬底上生长的Ni掺杂CdAs薄膜，研究了不同温度下的圆偏振光电流效应(CPGE)。发现CPGE电流的产生源于Ni掺杂CdAs薄膜中晶格应变和磁性掺杂引起的结构对称性破坏，这与未掺杂的薄膜类似。然而，在相同实验条件下，Ni掺杂CdAs薄膜中产生的CPGE电流比未掺杂薄膜中的CPGE电流小约两个数量级，并且呈现出复杂的温度变化。而未掺杂薄膜中的CPGE电流随温度升高总体呈增加趋势。讨论了Ni掺杂CdAs薄膜中CPGE电流产生效率大幅降低及其随温度的复杂变化是由于磁性杂质深能级对光生载流子的有效俘获，以及引入磁性掺杂剂时额外的强杂质散射导致的动量弛豫增强。
