Superconducting gap structure in electron and hole-doped kagome crystals CsV<sub>3</sub>Sb<sub>5</sub>

ORAL

Abstract

It is well established that the parent superconducting kagome compound, CsV₃Sb5, exhibits a fully gapped Fermi surface, possibly with moderate gap anisotropy [1,2]. It has also been shown that hole-doped CsV3-xTixSb5 [3] and electron-doped CsV3Sb5-xSnx [4] display an unusual double-dome T–x phase diagram, distinct from any other charge density wave (CDW) coexisting with superconductivity (SC) system, showing a dip in Tc(x) at the composition xCDW, where the (CDW) vanishes. This behavior may suggest unconventional coexistence and competition between superconducting and CDW quantum orders. Here, we report precision measurements of the London penetration depth using tunnel-diode resonator frequency-domain susceptometry. Investigated selected compositions are: CsV3Sb4.68Sn0.32 and CsV2.85Ti0.15Sb5, located at the second domes maximums, and CsV3Sb4.88Sn0.12, situated between the domes at the pronounced minimum of Tc(x). We analyze the inferred superconducting gap structure, compare it to that of the parent compound, CsV₃Sb5, and discuss possible mechanisms leading to the observed differences.

References

[1] A. R. Kaczmarek et al., Phys. Rev. Mater. 9, 74802 (2025), doi:10.1103/6ztt-34xc

[2] M. Roppongi et al., Nat. Commun. 14, 667 (2023), doi:10.1038/s41467-023-36273-x

[3] G. Pokharel et al., doi:10.48550/arXiv.2506.13941

[4] Phys. Rev. Mater. 6, L041801 (2022), doi:10.1103/PhysRevMaterials.6.L041801

*This work was supported by the National Science Foundation Under Grant No. DMR-2219901. BSM, MAT and KRJ were supported by the U.S. Department of Energy (DOE), Office of Science, Basic Energy Sciences, Materials Science and Engineering Division. Ames National Laboratory is operated for the U.S. DOE by Iowa State University Under Contract No. DE-AC02-07CH11358. Work at UCSB was supported by the U.S. Department of Energy (DOE), Office of Basic Energy Sciences, Division of Materials Sciences and Engineering under grant no. DE-SC0020305.

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Publication: This paper is being prepared for submission.

Presenters

  • Ruslan Prozorov

    • Ames National Laboratory

Authors

  • Ruslan Prozorov

    • Ames National Laboratory

  • Kamal R Joshi

    • Iowa State University
    • Ames National Laboratory

  • Amlan Datta

    • Ames National Laboratory, Iowa State University

  • Bicky Singh Moirangthem

    • Ames National Laboratory, Iowa State University
    • Iowa State University

  • Andrea C Capa Salinas

    • University of California, Santa Barbara
    • University of California Santa Barbara

  • Stephen Wilson

    • University of California, Santa Barbara

  • Makariy A Tanatar

    • Ames National Laboratory