Ju Weiwei, Wang Donghui, Li Tongwei, Zhang Yi, Gao Zijian, Ren Lixian, Li Haisheng, Gong Shijing
College of Physics and Engineering, Henan Key Laboratory of Photoelectric Energy Storage Materials and Applications, Henan University of Science and Technology, Luoyang, 471023, China.
Department of Optoelectrics, East China Normal University, Shanghai 200062, China.
Phys Chem Chem Phys. 2020 Apr 29;22(16):9148-9156. doi: 10.1039/d0cp00627k.
Herein, the Rashba spin orbit coupling (SOC) of polar group III-VI chalcogenide XABY (A, B = Ga, In; X ≠ Y = S, Se, Te) monolayers is investigated based on density functional theory. The different electronegativities of X and Y atoms lead to an asymmetrical internal electric field in the XABY monolayer; this implies that the internal electric field between A and X is not equal to that between B and Y. Mirror symmetry breaking in the XABY monolayer induces a remarkable Rashba spin splitting (RSS) at the conduction band minimum (CBM). Moreover, it is demonstrated that an external electric field and an in-plane biaxial strain can affect the internal electric field by varying the charge distribution, and this further manipulates the RSS. Under a positive external electric field and tensile strain, the RSS at the CBM exhibits a near-linear increasing behavior, whereas under a negative external electric field and compressive strain, the RSS displays a monotonous decreasing pattern. In addition, we explored the influence of interlayer coupling and substrate on the RSS. The stacking pattern of bilayer structures has a significant impact on the RSS. The investigation of SInGaSe on the Si(111) substrate suggests that the Rashba band is situated inside the large band gap of the substrate. Overall, our investigations suggest that the polar group III-VI chalcogenides are promising candidates for future spintronic applications.
在此，基于密度泛函理论研究了极性III-VI族硫族化合物XABY（A、B = Ga、In；X ≠ Y = S、Se、Te）单层的Rashba自旋轨道耦合（SOC）。X和Y原子不同的电负性导致XABY单层中存在不对称的内部电场；这意味着A与X之间的内部电场不等于B与Y之间的内部电场。XABY单层中的镜面对称性破缺在导带最小值（CBM）处诱导出显著的Rashba自旋分裂（RSS）。此外，研究表明，外部电场和面内双轴应变可以通过改变电荷分布来影响内部电场，进而进一步操控RSS。在正外部电场和拉伸应变下，CBM处的RSS呈现近线性增加行为，而在负外部电场和压缩应变下，RSS呈现单调递减模式。此外，我们还探讨了层间耦合和衬底对RSS的影响。双层结构的堆叠模式对RSS有显著影响。对Si(111)衬底上的SInGaSe的研究表明，Rashba能带位于衬底的大带隙内。总体而言，我们的研究表明，极性III-VI族硫族化合物是未来自旋电子学应用的有前途的候选材料。
