Violation of Emergent Rotational Symmetry in the Hexagonal Kagome Superconductor CsV3Sb5

Abstract

Superconductivity is caused by electron pairs that are canonically isotropic, whereas some exotic superconductors are known to exhibit non-trivial anisotropy stemming from unconventional pairings. However, superconductors with hexagonal symmetry, the highest rotational symmetry allowed in crystals, exceptionally have strong constraint that is called emergent rotational symmetry (ERS): anisotropic properties should be very weak especially near the critical temperature Tc even for unconventional pairings such as d-wave states. Here, we investigate superconducting anisotropy of the recently-found hexagonal Kagome superconductor CsV3Sb5, which is known to exhibit various intriguing phenomena originating from its undistorted Kagome lattice formed by vanadium atoms. Based on calorimetry performed under accurate two-axis field-direction control, we discover a combination of six- and two-fold anisotropies in the in-plane upper critical field. Both anisotropies, robust up to very close to Tc, are beyond predictions of standard theories. We infer that this clear ERS violation with nematicity is best explained by multi-component nematic superconducting order parameter in CsV3Sb5 intertwined with symmetry breakings caused by the underlying charge-density-wave order.

35 pages, 5 figures, 1 table, 7 extended figures

References in corpus (17)

• CsV${}_3$Sb${}_5$: a ${\mathbb{Z}}_2$ topological kagome metal with a superconducting ground state
• Roton pair density wave and unconventional strong-coupling superconductivity in a topological kagome metal
• Nature of unconventional pairing in the kagome superconductors AV${}_3$Sb${}_5$
• Multiband superconductivity with sign-preserving order parameter in kagome superconductor CsV3Sb5
• Odd-parity topological superconductor with nematic order: Application to CuxBi2Se3
• Twofold symmetry of $c$-axis resistivity in topological kagome superconductor CsV${}_3$Sb${}_5$ with in-plane rotating magnetic field
• Three-state nematicity and magneto-optical Kerr effect in the charge density waves in kagome superconductors
• s-wave superconductivity in kagome metal CsV${}_3$Sb${}_5$ revealed by ${}^{121/123}$Sb NQR and ${}^{51}$V NMR measurements
• Nodeless superconductivity in the kagome metal CsV${}_3$Sb${}_5$
• Multiple Energy Scales and Anisotropic Energy Gap in the Charge-Density-Wave Phase of Kagome Superconductor CsV3Sb5
• Anisotropic superconducting properties of Kagome metal CsV3Sb5
• Mechanism of exotic density-wave and beyond-Migdal unconventional superconductivity in kagome metal AV3Sb5 (A=K, Rb, Cs)
• Nematic superconductivity in doped Bi2Se3 topological superconductors
• Evidence of a hidden flux phase in the topological kagome metal CsV${}_3$Sb${}_5$
• Bulk evidence of anisotropic $s$-wave pairing with no sign change in the kagome superconductor CsV${}_3$Sb${}_5$
• Nodal superconductivity and superconducting domes in the topological Kagome metal CsV3Sb5
• Structural evolution of the kagome superconductors $A$V${}_3$Sb${}_5$ ($A$ = K, Rb, and Cs) through charge density wave order

Cited by in corpus (7)

• AV${}_3$Sb${}_5$ kagome superconductors: a review with transport measurements
• Observation of Fermi-surface-dependent anisotropic Cooper pairing in kagome superconductor CsV3Sb5
• Fully-gapped superconductivity with rotational symmetry breaking in pressurized kagome metal CsV${}_3$Sb${}_5$
• Quantum-metric-induced giant and reversible nonreciprocal transport phenomena in chiral loop-current phases of kagome metals
• Two-dimensional superconductivity in a thick exfoliated kagome film
• Antiferromagnetic Order and Magnetic Frustration in the Honeycomb Heavy-Fermion System Ce(Pt${}_{1-x}$Pd${}_x$)${}_6$Al${}_3$: ${}^{27}$Al and ${}^{195}$Pt NMR Studies
• Vector pulse magnet