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Synthesis of Co-Doped MoS2 Monolayers with Enhanced Valley Splitting |
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| Authors: | Jiadong Zhou Junhao Lin Hunter Sims Chongyun Jiang Chunxiao Cong John A Brehm Zhaowei Zhang Lin Niu Yu Chen Yao Zhou Yanlong Wang Fucai Liu Chao Zhu Ting Yu Kazu Suenaga Rohan Mishra Sokrates T Pantelides Zhen-Gang Zhu Weibo Gao Zheng Liu Wu Zhou |
| Affiliation: | 1. School of Materials Science and Engineering, Nanyang Technological University, Singapore, 639798 Singapore;2. National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, 305–8565 Japan
Department of Physics, Southern University of Science and Technology, Shenzhen, 518055 China;3. Department of Physics and Astronomy, Vanderbilt University, Nashville, TN, 37235 USA Materials Science and Technology Division, Oak Ridge National Lab, Oak Ridge, TN, 37831 USA;4. Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 637371 Singapore College of electronic information and optical engineering, Nankai University, Tianjin, 300350 China;5. Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 637371 Singapore State Key Laboratory of ASIC & System, School of Information Science and Technology, Fudan University, Shanghai, 200433 P. R. China;6. Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 637371 Singapore;7. National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, 305–8565 Japan;8. Department of Mechanical Engineering and Materials Science and Institute of Materials Science and Engineering, Washington University in St. Louis, St. Louis, MO, 63130 USA;9. School of Electronic, Electrical and Communication Engineering, University of Chinese Academy of Science, Beijing, 100049 China;10. CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing, 100049 China |
| Abstract: | Internal magnetic moments induced by magnetic dopants in MoS2 monolayers are shown to serve as a new means to engineer valley Zeeman splitting (VZS). Specifically, successful synthesis of monolayer MoS2 doped with the magnetic element Co is reported, and the magnitude of the valley splitting is engineered by manipulating the dopant concentration. Valley splittings of 3.9, 5.2, and 6.15 meV at 7 T in Co-doped MoS2 with Co concentrations of 0.8%, 1.7%, and 2.5%, respectively, are achieved as revealed by polarization-resolved photoluminescence (PL) spectroscopy. Atomic-resolution electron microscopy studies clearly identify the magnetic sites of Co substitution in the MoS2 lattice, forming two distinct types of configurations, namely isolated single dopants and tridopant clusters. Density functional theory (DFT) and model calculations reveal that the observed enhanced VZS arises from an internal magnetic field induced by the tridopant clusters, which couples to the spin, atomic orbital, and valley magnetic moment of carriers from the conduction and valence bands. The present study demonstrates a new method to control the valley pseudospin via magnetic dopants in layered semiconducting materials, paving the way toward magneto-optical and spintronic devices. |
| Keywords: | chemical vapor deposition Co doping MoS2 2D materials valley splitting |