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Journal article
Charge density waves and electronic properties of superconducting kagome metals
Physical review letters, Vol.127(4), 046401
10/Mar/2021
Abstract
Kagome metals $A$V$_3$Sb$_5$ ($A=$ K, Rb, and Cs) exhibit intriguing superconductivity below $0.9 \sim 2.5 $ K, a charge density wave (CDW) transition around $80\sim 100 $ K, and $\mathbb{Z}_{2}$ topological surface states. The nature of the CDW phase and its relation to superconductivity remains elusive. In this work, we investigate the electronic and structural properties of CDW by first-principles calculations. We reveal an inverse Star of David deformation as the $2\times2\times2$ CDW ground state of the kagome lattice. The kagome lattice shows softening breathing-phonon modes, indicating the structural instability. However, electrons play an essential role in the CDW transition via Fermi surface nesting and van Hove singularity. The inverse Star of David structure agrees with recent experiments by scanning tunneling microscopy (STM). The CDW phase inherits the nontrivial $\mathbb{Z}_{2}$-type topological band structure. Further, we find that the electron-phonon coupling is too weak to account for the superconductivity $T_c$ in all three materials. It implies the existence of unconventional pairing of these kagome metals. Our results provide essential knowledge toward understanding the superconductivity and topology in kagome metals.
Details
- Title
- Charge density waves and electronic properties of superconducting kagome metals
- Creators
- Hengxin Tan - 972WIS_INST___90Yizhou Liu - 972WIS_INST___90Ziqiang Wang - Boston CollegeBinghai Yan - 972WIS_INST___90
- Resource Type
- Journal article
- Publication Details
- Physical review letters, Vol.127(4), 046401; 10/Mar/2021
- Language
- English
- DOI
- https://doi.org/10.1103/PhysRevLett.127.046401
- Grant note
- We thank H. Chen for inspiring discussions and A. Perara for help in calculations. B. Y. acknowledges the financial support by the Willner Family Leadership Institute for the Weizmann Institute of Science, the Benoziyo Endowment Fund for the Advancement of Science, Ruth and Herman Albert Scholars Program for New Scientists, the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (Grant No. 815869), and ISF MAFAT Quantum Science and Technology (2074/19). Z. W. is supported by the U.S. Department of Energy, Basic Energy Sciences Grant No. DE-FG02-99ER45747.
- Record Identifier
- 993280840603596
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