2021/04/12 by Zhengguo Wang, Sheng Ma, Wang, Zhengguo +31 · 2 citations
Physics and Astronomy · #Topological Materials and Phenomena #Advanced Condensed Matter Physics #Quantum, superfluid, helium dynamics
paper · pdf · doi:10.48550/arxiv.2104.05556
CsV3Sb5 is a newly discovered Kagome superconductor that attracts great interest due to its topological nontrivial band structure and the coexistence of superconductivity and charge-density-wave (CDW) with many exotic properties. Here, we report the detailed characterization of the CDW gap in high-quality CsV3Sb5 single crystals using high-resolution angle-resolved photoemission spectroscopy. We find that the CDW gap is strongly momentum dependent. While gapped around the M point, the electronic states remain gapless around the Γ point and along the Γ-K direction. Such momentum dependence indicates that the CDW is driven by the scattering of electrons between neighboring M points, where the band structure hosts multiple saddle points and the density of state diverges near the Fermi level. Our observations of the partially gapped Fermi surface and strongly momentum-dependent CDW gap not only provide a foundation for uncovering the mechanism of CDW in CsV3Sb5, but also shed light on the understanding of how the CDW coexists with superconductivity in this topological Kagome superconductor.