Probing the superconductivity of kagome metal CsV₃Sb₅ with self-field critical current

The kagome metal CsV₃Sb₅ features an interesting interplay between the charge-density-wave (CDW) order and superconductivity. The CDW phase is complex and potentially breaks the time-reversal symmetry, which can result in an exotic superconducting state. Here, we use the self-field critical current (I_c,sf) as a proxy to investigate the superconducting gap [1]. We show that our I_c,sf data can be understood when considering a single s-wave gap. Furthermore, the superconducting critical temperature is insensitive to disorder, leading us to conclude that CsV₃Sb₅ is a conventional s-wave superconductor. Finally, we measure I_c,sf under pressure using a device-integrated diamond anvil cell [2,3]. In particular, we investigate the superconducting state at pressures where the CDW phase can be removed. Our results show that s-wave gap symmetry is retained irrespective of the presence of the CDW order.

[1] Zhang et al., Nano Lett. 23, 872 (2023)

[2] Xie et al., Nano Lett. 21, 9310 (2021)

[3] Ku et al., Rev. Sci. Instrum. 93, 083912 (2022)