Nature Communications, 14, 5230 (2023)

Discovery and construction of surface kagome electronic states induced by p-d electronic hybridization in Co3Sn2S2

Li Huang^{1, 2}, Xianghua Kong^{3, 4, 5}, Qi Zheng^{1, 2}, Yuqing Xing^{1, 2}, Hui Chen^{1, 2}, Yan Li^{1, 2}, Zhixin Hu⁶, Shiyu Zhu^{1, 2}, Jingsi Qiao^{4, 7}, YuYang Zhang³, Haixia Cheng⁴, Zhihai Cheng⁴, Xianggang Qiu^{1, 2}, Enke Liu^{1, 2}, Hechang Lei⁴, Xiao Lin², Ziqiang Wang⁸, Haitao Yang^{1, 2}, Wei Ji^{4, 9} and Hong-Jun Gao^{1, 2, 10}

1 Beijing National Center for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, 100190 Beijing, China.

2 School of Physical Sciences, University of Chinese Academy of Sciences, 100190 Beijing, China.

3 College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China.

4 Beijing Key Laboratory of Optoelectronic Functional Materials & Micro-Nano Devices, Department of Physics, Renmin University of China, 100872 Beijing, China.

5 Centre for the Physics of Materials and Department of Physics, McGill University, Montreal, QC H3A 2T8, Canada.

6 Center for Joint Quantum Studies and Department of Physics, Institute of Science, Tianjin University, 300350 Tianjin, China.

7 MIIT Key Laboratory for Low-Dimensional QuantumStructure and Devices, School of Integrated Circuits and Electronics, Beijing Institute of Technology, 100081 Beijing,China.

8 Department of Physics, Boston College, Chestnut Hill, MA, USA.

9 Key Laboratory of Quantum State Construction and Manipulation (Ministry of Education), Renmin University of China, 100872 Beijing, China.

10 Hefei National Laboratory, 230088 Hefei, Anhui, China.

* htyang@iphy.ac.cn, wji@ruc.edu.cn, hjgao@iphy.ac.cn

Abstract

Kagome-lattice materials possess attractive properties for quantum computing applications, but their synthesis remains challenging. Herein, based on the compelling identification of the two cleavable surfaces of Co3Sn2S2, we show surface kagome electronic states (SKESs) on a Sn-terminated triangular Co3Sn2S2 surface. Such SKESs are imprinted by vertical p-d electronic hybridization between the surface Sn (subsurface S) atoms and the buried Co kagome-lattice network in the Co3Sn layer under the surface. Owing to the subsequent lateral hybridization of the Sn and S atoms in a corner-sharing manner, the kagome symmetry and topological electronic properties of the Co3Sn layer is proximate to the Sn surface. The SKESs and both hybridizations were verified via qPlus non-contact atomic force microscopy (nc-AFM) and density functional theory calculations. The construction of SKESs with tunable properties can be achieved by the atomic substitution of surface Sn (subsurface S) with other group III-V elements (Se or Te), which was demonstrated theoretically. This work exhibits the powerful capacity of nc-AFM in characterizing localized topological states and reveals the strategy for synthesis of large-area transition-metal-based kagome-lattice materials using conventional surface deposition techniques.