之字形的
光电流
凝聚态物理
密度泛函理论
自旋(空气动力学)
各向异性
自旋极化
圆极化
电荷(物理)
单层
物理
材料科学
光电子学
光学
纳米技术
量子力学
微带线
电子
热力学
数学
几何学
作者
Liwen Zhang,Yaqing Yang,Jun Chen,Lei Zhang
标识
DOI:10.1007/s11467-023-1307-1
摘要
Photogalvanic effect (PGE) occurs in materials with non-centrosymmetric structures when irradiated by linearly or circularly polarized light. Here, using non-equilibrium Green’s function combined with density functional theory (NEGF-DFT), we investigated the linear photogalvanic effect (LPGE) in monolayers of group-V elements (As, Sb, and Bi) by first-principles calculations. First, by designing a two-probe structure based on the group-V elements, we found a giant anisotropy photoresponse of As between the armchair and zigzag directions. Then, we analyzed Sb and Bi’s charge and spin photocurrent characteristics when considering the spin-orbit coupling (SOC) effect. It is found that when the polarization direction of linearly polarized light is parallel or perpendicular to the transport direction (θ = 0° or 90°), the spin up and spin down photoresponse in the armchair direction has the same magnitude and direction, leading to the generation of net charge current. However, in the zigzag direction, the spin up and spin down photoresponse have the same magnitude with opposite directions, leading to the generation of pure spin current. Furthermore, it is understood by analyzing the bulk spin photovoltaic (BSPV) coefficient from the symmetry point of view. Finally, we found that the net charge current generated in the armchair direction and the pure spin current generated in the zigzag direction can be further tuned with the increase of the material’s buckling height ∣h∣. Our results highlight that these group-V monolayers are promising candidates for novel functional materials, which will provide a broad prospect for the realization of ultra-thin ferroelectric devices in optoelectronics due to their spontaneous polarization characteristics and high Curie temperature.
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