Colossal c-axis response and lack of rotational symmetry breaking within the kagome plane of the CsV${}_3$Sb${}_5$ superconductor

Abstract

The kagome materials AV4${}_3$Sb${}_5$ (A = K, Rb, Cs) host an intriguing interplay between unconventional superconductivity and charge-density-waves. Here, we investigate CsV${}_3$Sb${}_5$ by combining high-resolution thermal-expansion, heat-capacity and electrical resistance under strain measurements. We directly unveil that the superconducting and charge-ordered states strongly compete, and that this competition is dramatically influenced by tuning the crystallographic c-axis. In addition, we report the absence of additional bulk phase transitions within the charge-ordered state, notably associated with rotational symmetry-breaking within the kagome planes. This suggests that any breaking of the C${}_6$ invariance occurs via different stacking of C${}_6$-symmetric kagome patterns. Finally, we find that the charge-density-wave phase exhibits an enhanced A${}_{1g}$-symmetric elastoresistance coefficient, whose large increase at low temperature is driven by electronic degrees of freedom.

Cited by in corpus (1)

• Correlated order at the tipping point in the kagome metal CsV${}_3$Sb${}_5$