Twofold van Hove singularity and origin of charge order in topological kagome superconductor CsV<sub>3</sub>Sb<sub>5</sub>

ORAL

Abstract

The layered vanadium antimonides AV3Sb5 (A = K, Rb, Cs) are a recently discovered family of topological kagome metals that exhibit a range of strongly correlated electronic phases including charge order and superconductivity. However, it is not yet understood how the singularities inherent to the kagome electronic structure are linked to the observed many-body phases. Here, we combine angle-resolved photoemission spectroscopy and density functional theory to reveal multiple kagome-derived van Hove singularities (vHS) coexisting near the Fermi level of CsV3Sb5 and analyze their contribution to electronic symmetry breaking. The vHS in CsV3Sb5 are characterized by two distinct sublattice flavors – pure (p)-type and mixed (m)-type – which critically determines the pairing symmetry and ground states emerging in AV3Sb5 series. We establish that, among the multiple vHS in CsV3Sb5, the m-type vHS of the dxz/dyz kagome band and the p-type vHS of the dxy/dx2-y2 kagome band cross the Fermi level to allow electronic symmetry breaking. The former band exhibits pronounced Fermi surface nesting, while the latter contributes via higher-order vHS. Our work reveals the essential role of kagome-derived vHS for the collective phenomena realized in the AV3Sb5 family.

*This work was supported by the STC Center for Integrated Quantum Materials, NSF Grant No. DMR-1231319.

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Publication: M. Kang et al., arXiv:2105.01689 (2021).

Presenters

  • Min Gu Kang

    • Massachusetts Institute of Technology MI

Authors

  • Min Gu Kang

    • Massachusetts Institute of Technology MI

  • Shiang Fang

    • Rutgers University, New Brunswick
    • Massachusetts Institute of Technology

  • Jeong-Kyu Kim

    • Pohang University of Science and Technology

  • Brenden Ortiz

    • University of California, Santa Barbara

  • Sae-Hee Ryu

    • Lawrence Berkeley National Laboratory

  • Jimin Kim

    • Institute for Basic Science

  • Jonggyu Yoo

    • Pohang University of Science and Technology

  • Giorgio Sangiovanni

    • Julius-Maximilians University of Wuerzbu
    • Julius-Maximilians University of Wuerzburg

  • Domenico Di Sante

    • University of Bologna
    • Center for Computational Quantum Physics, Flatiron Institute

  • Byeong-Gyu Park

    • Pohang Accelerator Laboratory

  • Christopher Jozwiak

    • Lawrence Berkeley National Laboratory
    • Lawrence Berkeley National Lab
    • E. O. Lawrence Berkeley National Laboratory
    • lawrence berkeley lab
    • Advanced Light Source, Lawrence Berkeley National Laboratory

  • Aaron Bostwick

    • Lawrence Berkeley National Laboratory
    • Lawrence Berkeley National Lab
    • E. O. Lawrence Berkeley National Laboratory
    • lawrence berkeley lab
    • Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley

  • Eli Rotenberg

    • Lawrence Berkeley National Laboratory

  • Efthimios Kaxiras

    • Harvard University

  • Stephen D Wilson

    • University of California, Santa Barbara

  • Jae-Hoon Park

    • Pohang Univ of Sci & Tech

  • Riccardo Comin

    • Massachusetts Institute of Technology MI
    • Massachusetts Institute of Technology
    • Massachusetts Institute of Technology MIT