Quantum-Confined Tunable Ferromagnetism on the Surface of a Van der Waals Antiferromagnet NaCrTe<sub>2</sub>
The surface of three-dimensional materials provides an ideal and versatile platform to explore quantum-confined physics. Here, we systematically investigate the electronic structure of Na-intercalated CrTe<sub>2</sub>, a van der Waals antiferromagnet, using angle-resolved photoemission spectroscopy and <i>ab initio</i> calculations. The measured band structure deviates from the calculation of bulk NaCrTe<sub>2</sub> but agrees with that of ferromagnetic monolayer CrTe<sub>2</sub>. Consistently, we observe unexpected exchange splitting of the band dispersions, persisting well above the Néel temperature of bulk NaCrTe<sub>2</sub>. We argue that NaCrTe<sub>2</sub> features a quantum-confined 2D ferromagnetic state in the topmost surface layer due to strong ferromagnetic correlation in the CrTe<sub>2</sub> layer. Moreover, the exchange splitting and the critical temperature can be controlled by surface doping of alkali-metal atoms, suggesting the feasibility of tuning the surface ferromagnetism. Our work not only presents a simple platform for exploring tunable 2D ferromagnetism but also provides important insights into the quantum-confined low-dimensional magnetic states.
Authors
- Runzhe Xu (ORCID: https://orcid.org/0000-0002-1682-8916)
- Houke Chen (ORCID: https://orcid.org/0000-0002-0261-7480)
- Sailong Ju
- Jieyi Liu (ORCID: https://orcid.org/0000-0001-6588-5987)
- Jiangang Guo (ORCID: https://orcid.org/0000-0003-3880-3012)
- M. Shi (ORCID: https://orcid.org/0000-0002-6090-8219)
- Yidian Li (ORCID: https://orcid.org/0009-0004-2189-109X)
- Yiheng Yang (ORCID: https://orcid.org/0000-0003-1840-2748)
- Zhongkai Liu (ORCID: https://orcid.org/0000-0003-3373-8039)
- Xian Du
- N. C. Plumb (ORCID: https://orcid.org/0000-0002-2334-8494)
- Wenxuan Zhao (ORCID: https://orcid.org/0000-0003-4444-3674)
- Lexian Yang (ORCID: https://orcid.org/0000-0002-0078-1797)
- Yulin Chen (ORCID: https://orcid.org/0000-0001-8960-9725)
- Xiaolong Chen (ORCID: https://orcid.org/0009-0004-6149-3002)
- Kaiyi Zhai
- Junjie Wang (ORCID: https://orcid.org/0009-0001-9328-5863)
Institutions
- Paul Scherrer Institute (CH)
- ShanghaiTech University (CN)
- University of Oxford (GB)
- Beijing Academy of Quantum Information Sciences (CN)
- Institute of Physics (CN)
- University of Chinese Academy of Sciences (CN)
- Zhejiang University (CN)
- Tsinghua University (CN)
Publication Details
- Journal
- Nano Letters
- Published
- 2024-08-05
- DOI
- https://doi.org/10.1021/acs.nanolett.4c01542
- Citations
- 2
- Primary Topic
- 2D Materials and Applications
- Type
- article
- Field-Weighted Citation Impact
- 0.23
Funders
- National Natural Science Foundation of China
- Tsinghua University
- Natural Science Foundation of Beijing Municipality
- National Key Research and Development Program of China