AI 中文总结
本研究通过钒掺杂WS₂单层实现谷不对称性，增强谷极化效率，为缺陷工程二维材料的谷电子学应用奠定基础。
AI 中文摘要
过渡金属二硫族化物（TMD）单层为通过谷自由度编码和操控信息提供了一个创新平台。尽管迄今已报道了独特的谷相关物理现象，但实际应用仍需要对谷极化效率和谷塞曼效应进行先进的控制。最近，有报道称将自旋极化的金属原子作为替代缺陷引入TMD单层，可打破时间反演对称性，从而诱导室温铁磁有序并增强谷相关的光学响应。在此，我们报道了钒掺杂WS$_2$单层中的谷不对称性。在给定的磁极化下，一个谷表现出比另一个谷更大的塞曼斜率和圆偏振度。此外，掺杂样品中的整体圆偏振度约为未掺杂WS$_2$单层的两倍。掺杂结构中的密度泛函理论计算表明，由于自旋依赖的杂化导致导带边不同的能量位移，使得谷间激子能量不同，这与实验观测一致。我们的结果为基于缺陷工程二维材料的谷电子学技术铺平了道路。
英文摘要
Transition metal dichalcogenide (TMD) monolayers offer an innovative platform for encoding and manipulating information through the valley degree of freedom. While unique valley-related physical phenomena have been reported so far, practical applications still require advanced control over the valley polarization efficiency and the valley Zeeman effect. Recently, the introduction of spin-polarized metal atoms as substitutional defects was reported to break the time-reversal symmetry in TMD monolayers, consequently inducing a room-temperature ferromagnetic ordering and enhancing the valley-dependent optical responses. Here, we report valley asymmetries for vanadium-doped WS$_2$ monolayers. With a given magnetic polarization, one valley exhibits larger Zeeman slope and degree of circular polarization than the other valley. Additionally, the overall degree of circular polarization in the doped samples is approximately twice that of the pristine WS$_2$ monolayer. Density functional theory calculations in the doped structure show that different energy shifts in conduction band edges due to spin-dependent hybridization lead to different exciton energies between valleys, which is consistent with the experimental observations. Our results pave the way for valleytronic technologies based on defect-engineered two-dimensional materials.
