Li Qi, Zhao Xiaoxu, Deng Longjiang, Shi Zhongtai, Liu Sheng, Wei Qilin, Zhang Linbo, Cheng Yingchun, Zhang Li, Lu Haipeng, Gao Weibo, Huang Wei, Qiu Cheng-Wei, Xiang Gang, Pennycook Stephen John, Xiong Qihua, Loh Kian Ping, Peng Bo
National Engineering Research Center of Electromagnetic Radiation Control Materials, School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu, 611731, China.
Department of Materials Science and Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore 117575, Singapore.
ACS Nano. 2020 Apr 28;14(4):4636-4645. doi: 10.1021/acsnano.0c00291. Epub 2020 Mar 17.
The "Zeeman effect" offers unique opportunities for magnetic manipulation of the spin degree of freedom (DOF). Recently, valley Zeeman splitting, referring to the lifting of valley degeneracy, has been demonstrated in two-dimensional transition metal dichalcogenides (TMDs) at liquid helium temperature. However, to realize the practical applications of valley pseudospins, the valley DOF must be controllable by a magnetic field at room temperature, which remains a significant challenge. Magnetic doping in TMDs can enhance the Zeeman splitting; however, to achieve this experimentally is not easy. Here, we report unambiguous magnetic manipulation of valley Zeeman splitting at 300 K ( = -6.4) and 10 K ( = -11) in a CVD-grown Fe-doped MoS monolayer; the effective Landé factor can be tuned to -20.7 by increasing the Fe dopant concentration, which represents an approximately 5-fold enhancement as compared to undoped MoS. Our measurements and calculations reveal that the enhanced splitting and factors are due to the Heisenberg exchange interaction of the localized magnetic moments (Fe 3d electrons) with MoS through the d-orbital hybridization.
“塞曼效应”为自旋自由度（DOF）的磁性操控提供了独特机遇。最近，在液氦温度下，二维过渡金属二硫属化物（TMDs）中已证实了谷塞曼分裂，即谷简并的解除。然而，要实现谷赝自旋的实际应用，谷自由度必须在室温下通过磁场可控，这仍然是一个重大挑战。TMDs中的磁性掺杂可增强塞曼分裂；然而，通过实验实现这一点并不容易。在此，我们报告了在化学气相沉积（CVD）生长的铁掺杂单层MoS₂中，在300 K（ = -6.4）和10 K（ = -11）下对谷塞曼分裂进行的明确磁性操控；通过增加铁掺杂剂浓度，有效朗德因子可调整至-20.7，与未掺杂的MoS₂相比，这代表了约5倍的增强。我们的测量和计算表明，增强的分裂和因子归因于局域磁矩（Fe 3d电子）通过d轨道杂化与MoS₂的海森堡交换相互作用。
