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Chin. Phys. B, 2026, Vol. 35(3): 036801    DOI: 10.1088/1674-1056/ae2f53
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Real-space imaging of kagome flat band localization in Fe3Sn2

Yifan Wang(汪逸凡)1,2,3, Lili Jiang(蒋利利)1,2,3, Qiang Zhang(张强)1,2,3, Zhiyong Lin(林志勇)1,2,3, Hui Zhang(张汇)1,2,3,†, and Changgan Zeng(曾长淦)1,2,3
1 CAS Key Laboratory of Strongly-Coupled Quantum Matter Physics, and Department of Physics, University of Science and Technology of China, Hefei 230026, China;
2 International Center for Quantum Design of Functional Materials (ICQD), Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, China;
3 Hefei National Laboratory, University of Science and Technology of China, Hefei 230088, China
Abstract  In geometrically frustrated lattices, flat bands can arise from destructive quantum interference, providing an ideal platform for exploring strong electron correlations. However, direct real-space evidence of their predicted atomic-scale electron localization remains elusive. By employing scanning tunneling microscopy/spectroscopy, with a focus on quasiparticle interference imaging, we demonstrate unambiguous atomic-scale localization of flat band electrons in the kagome metal Fe3Sn2. Crucially, quasiparticle interference imaging reveals a complete suppression of scattering wavevectors and standing waves exclusively at the flat band energy, indicating the absence of long-range coherent propagation. This disappearance of the quasiparticle interference signal, attributable to the non-propagating wavefunctions inherent to the kagome flat band, directly confirms real-space electron localization. These findings resolve the microscopic link between quantum interference and localization of flat band electrons, paving the way for engineering correlated quantum states.
Keywords:  scanning tunneling microscopy      kagome      flat band      electron localization      quasiparticle interference  
Received:  29 September 2025      Revised:  12 December 2025      Accepted manuscript online:  19 December 2025
PACS:  68.37.-d (Microscopy of surfaces, interfaces, and thin films)  
  68.37.Ef (Scanning tunneling microscopy (including chemistry induced with STM))  
  71.20.-b (Electron density of states and band structure of crystalline solids)  
  73.20.At (Surface states, band structure, electron density of states)  
Fund: This work was supported by the National Key Research and Development Program of China (Grant No. 2023YFA1406300), the Innovation Program for Quantum Science and Technology (Grant No. 2021ZD0302800), the National Natural Science Foundation of China (Grant Nos. 92165201, 12374458, 12488101, and 11974323), Anhui Provincial Key Research and Development Project (Grant No. 2023z04020008), the CAS Project for Young Scientists in Basic Research (Grant No. YSBR-046), the Fundamental Research Funds for the Central Universities (Grant No. WK9990000118), and the Strategic Priority Research Program of Chinese Academy of Sciences (Grant No. XDB0510200).
Corresponding Authors:  Hui Zhang, Changgan Zeng     E-mail:  huiz@ustc.edu.cn;cgzeng@ustc.edu.cn

Cite this article: 

Yifan Wang(汪逸凡), Lili Jiang(蒋利利), Qiang Zhang(张强), Zhiyong Lin(林志勇), Hui Zhang(张汇), and Changgan Zeng(曾长淦) Real-space imaging of kagome flat band localization in Fe3Sn2 2026 Chin. Phys. B 35 036801

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