Kagome structure originated as an old Asian Bamboo basket with both trigonal and hexagonal structures. Recently, the coexistence of charge density wave (CDW) state and superconductivity has been discovered in a new type of quasi-two-dimensional Kagome system AV3Sb5 with the kagome lattice of V atoms. Although the charge density wave and superconductivity have been investigated intensively, the non-trivial electronic band structure have been rarely studied.
Recently, a research team led by Prof. ZHU Xiangde from Hefei Institutes of Physical Science (HFIPS), Chinese Academy of Sciences and Prof. LEI Heichang from Renmin university, studied the quantum transport properties of CsV3Sb5 and proved topological non-mediocre electronic structure in it.
In this research, they analyzed the quantum oscillation of Shubnikov-de Haas (SdH) and the comparison with the theoretical calculation results in Steady High Magnetic Field Laboratory of HFIPS.
Although the superconductivity with Tc = 2.8K (-270.3OC) has been discovered, the predicted nontrivial topological band structures still have not confirmed experimentally. By magneto-resistance measurement up to 35 Tesals at low temperature, Shubnikov–de Haas (SdH) oscillations(which means the resistivity has a oscillation part versus magnetic field) with clear evidences of non-trivial topological band structures of CsV3Sb5 have observed. All the experimental results are consistent with the theoretical ones.
These results indicate that the kagome material CsV3Sb5 exhibits non-trivial topological electronic band structure, except for the reported charge density wave and superconductivity.
Their findings have been published on Physical Review Letters.
(a) a traditional Asian Bamboo basket; (b) the fine structure of bamboo knitting; (c) The crystal structure of CsV3Sb5 viewed from c-axis. (Image by ZHU Xiangde)
Quantum resistivity SdH osillation under high magnetic field (Image by ZHU Xiangde)