Xie Xing, Wu Biao, Ding Junnan, Li Shaofei, Chen Junying, He Jun, Liu Zongwen, Wang Jian-Tao, Liu Yanping
Institute of Quantum Physics, School of Physics, Central South University, 932 South Lushan Road, Changsha, Hunan 410083, People's Republic of China.
State Key Laboratory of Precision Manufacturing for Extreme Service Performance, Central South University, 932 South Lushan Road, Changsha, Hunan 410083, People's Republic of China.
Nano Lett. 2024 Jul 31;24(30):9186-9194. doi: 10.1021/acs.nanolett.4c01327. Epub 2024 Jul 16.
The interaction between light and moiré superlattices presents a platform for exploring unique light-matter phenomena. Tailoring these optical properties holds immense potential for advancing the utilization of moiré superlattices in photonics, optoelectronics, and valleytronics. However, the control of the optical polarization state in moiré superlattices, particularly in the presence of moiré effects, remains elusive. Here, we unveil the emergence of optical anisotropy in moiré superlattices by constructing twisted WSe/WSe/SiP heterostructures. We report a linear polarization degree of ∼70% for moiré excitons, attributed to the spatially nonuniform charge distribution, corroborated by first-principles calculations. Furthermore, we demonstrate the modulation of this linear polarization state via the application of a magnetic field, resulting in polarization angle rotation and a magnetic-field-dependent linear polarization degree, influenced by valley coherence and moiré potential effects. Our findings demonstrate an efficient strategy for tuning the optical polarization state of moiré superlattices using heterointerface engineering.
光与莫尔超晶格之间的相互作用为探索独特的光与物质现象提供了一个平台。定制这些光学特性对于推动莫尔超晶格在光子学、光电子学和谷电子学中的应用具有巨大潜力。然而，在莫尔超晶格中控制光学偏振态，特别是在存在莫尔效应的情况下，仍然难以实现。在这里，我们通过构建扭曲的WSe/WSe/SiP异质结构揭示了莫尔超晶格中光学各向异性的出现。我们报告了莫尔激子的线性偏振度约为70%，这归因于空间不均匀的电荷分布，第一性原理计算证实了这一点。此外，我们通过施加磁场展示了对这种线性偏振态的调制，导致偏振角旋转和与磁场相关的线性偏振度，这受到谷相干和莫尔势效应的影响。我们的发现展示了一种利用异质界面工程来调节莫尔超晶格光学偏振态的有效策略。
