Yan Xuefei, Ke Qingqing, Cai Yongqing
Institute of Applied Physics and Materials Engineering, University of Macau, People's Republic of China.
School of Microelectronics Science and Technology, Sun Yat-sen University, Zhuhai 519082, People's Republic of China.
Nanotechnology. 2022 Apr 7;33(26). doi: 10.1088/1361-6528/ac6007.
By utilizing the tight-binding method, the electronic spectrum and states distribution of square Janus monolayer black arsenic phosphorus (b-AsP) quantum dots (QDs) in the presence of a perpendicular magnetic field are explored. Strong in-gap states of b-AsP QDs, whose probability densities are distributed on the armchair boundary (armchair edge states) appear in the energy gap of host perfect two-dimensional b-AsP. The corresponding energy levels of the armchair edge states can degenerate to the Landu energy levels upon applying a perpendicular magnetic field. When an in-plane polarized light is introduced, due to the presence of armchair edge states, the edge-to-edge transitions are mainly induced from the armchair edge (hole) states to zigzag edge (electron) states. The optical absorption undergoes blue shift as a function of the magnetic field. Our work suggests tunable optical properties via modulating the armchair edge states of a b-AsP QD and provides a theoretical basis for the design of b-AsP-based optoelectronic devices.
通过利用紧束缚方法，研究了方形Janus单层黑砷磷（b-AsP）量子点（QD）在垂直磁场存在下的电子光谱和态分布。b-AsP量子点的强能隙态，其概率密度分布在扶手椅边界（扶手椅边缘态），出现在主体完美二维b-AsP的能隙中。施加垂直磁场时，扶手椅边缘态的相应能级可简并为朗道能级。当引入面内偏振光时，由于存在扶手椅边缘态，边到边跃迁主要由扶手椅边缘（空穴）态诱导至锯齿边缘（电子）态。光吸收随磁场发生蓝移。我们的工作表明通过调制b-AsP量子点的扶手椅边缘态可实现可调谐光学性质，并为基于b-AsP的光电器件设计提供了理论基础。
