Bulk evidence of anisotropic $s$-wave pairing with no sign change in the kagome superconductor CsV${}_3$Sb${}_5$

Abstract

The recently discovered kagome superconductors $A$V${}_3$Sb${}_5$ ($A$ = K, Rb, Cs) possess a unique band structure with van Hove singularities and Dirac dispersions, in which unusual charge-density-wave (CDW) orders with time-reversal and rotational symmetry breaking have been reported. One of the most crucial unresolved issues is identifying the symmetry of the superconductivity that develops inside the CDW phase. Theory predicts a variety of unconventional superconducting symmetries, including exotic states with chiral and topological properties accompanied by a sign-changing superconducting gap. Experimentally, however, the phase information on the superconducting gap in $A$V${}_3$Sb${}_5$ is still lacking. Here we report the electron irradiation effects in CsV${}_3$Sb${}_5$ using introduced impurities as a phase-sensitive probe of superconductivity. Our magnetic penetration depth measurements reveal that with increasing impurities, a highly anisotropic fully-gapped state changes gradually to an isotropic full-gap state without passing through a nodal state. Furthermore, transport measurements under high pressure show that the double superconducting dome in the pressure-temperature phase diagram survives against sufficient impurities. These results are strong bulk evidence that CsV${}_3$Sb${}_5$ is a non-chiral, anisotropic $s$-wave superconductor with no sign change both at ambient and high pressure, which provides a clue to understanding the relationship between CDW and superconductivity in kagome superconductors.

22 pages, 4 figures

References in corpus (25)

• CsV${}_3$Sb${}_5$: a ${\mathbb{Z}}_2$ topological kagome metal with a superconducting ground state
• Discovery of unconventional chiral charge order in kagome superconductor KV3Sb5
• Roton pair density wave and unconventional strong-coupling superconductivity in a topological kagome metal
• Cascade of correlated electron states in a kagome superconductor CsV3Sb5
• Unconventional Fermi surface instabilities in the Kagome Hubbard Model
• Time-reversal symmetry-breaking charge order in a kagome superconductor
• Charge density waves and electronic properties of superconducting kagome metals
• Superconductivity in the ${\mathbb{Z}}_2$ kagome metal KV${}_3$Sb${}_5$
• Double superconducting dome and triple enhancement of Tc in the kagome superconductor CsV3Sb5 under high pressure
• Superconductivity and normal-state properties of kagome metal RbV3Sb5 single crystals
• Electronic instabilities of kagome metals: saddle points and Landau theory
• Nature of unconventional pairing in the kagome superconductors AV${}_3$Sb${}_5$
• Rotation symmetry breaking in the normal state of a kagome superconductor KV3Sb5
• Multiband superconductivity with sign-preserving order parameter in kagome superconductor CsV3Sb5
• Twofold symmetry of $c$-axis resistivity in topological kagome superconductor CsV${}_3$Sb${}_5$ with in-plane rotating magnetic field
• s-wave superconductivity in kagome metal CsV${}_3$Sb${}_5$ revealed by ${}^{121/123}$Sb NQR and ${}^{51}$V NMR measurements
• Theory of the charge-density wave in $A$V${}_3$Sb${}_5$ kagome metals
• Tunable nodal kagome superconductivity in charge ordered RbV3Sb5
• Nodeless superconductivity in the kagome metal CsV${}_3$Sb${}_5$
• Mechanism of exotic density-wave and beyond-Migdal unconventional superconductivity in kagome metal AV3Sb5 (A=K, Rb, Cs)
• Microscopic evidence for anisotropic multigap superconductivity in the CsV${}_3$Sb${}_5$ kagome superconductor
• Disorder-induced topological change of the superconducting gap structure in iron pnictides
• Strongly correlated superconductivity in a copper-based metal-organic framework with a perfect kagome lattice
• Coexistence of Tri-Hexagonal and Star-of-David Pattern in the Charge Density Wave of the Kagome Superconductor AV${}_3$Sb${}_5$
• Nodal superconductivity and superconducting domes in the topological Kagome metal CsV3Sb5

Cited by in corpus (44)

• Quantum states and intertwining phases in kagome materials
• AV${}_3$Sb${}_5$ Kagome Superconductors: Progress and Future Directions
• Superconducting diode effect and interference patterns in Kagome CsV3Sb5
• Nodeless superconductivity in kagome metal CsV${}_3$Sb${}_5$ with and without time reversal symmetry breaking
• Charge-loop current order and Z3 nematicity mediated by bond-order fluctuations in kagome metal AV3Sb5 (A=Cs,Rb,K)
• Unconventional superconductivity protected from disorder on the kagome lattice
• Electronic Landscape of Kagome Superconductors $\text{A}$V${}_3$Sb${}_5$ ($\text{A}$ = K, Rb, Cs) from Angle-Resolved Photoemission Spectroscopy
• Drastic magnetic-field-induced chiral current order and emergent current-bond-field interplay in kagome metals
• Superconductivity from Orbital-Selective Electron-Phonon Coupling in $A{\mathrm{V}}_3{\mathrm{Sb}}_5$
• Unconventional gapping behavior in a kagome superconductor
• Kagome metals
• Defect-Induced Low-Energy Majorana Excitations in the Kitaev Magnet $\alpha$-RuCl${}_3$
• Evidence of a distinct collective mode in Kagome superconductors
• Similarities and Differences in the Fermiology of Kagome Metals AV${}_3$Sb${}_5$ (A=K, Rb, Cs) Revealed by Shubnikov-de Haas Oscillations
• Violation of Emergent Rotational Symmetry in the Hexagonal Kagome Superconductor CsV3Sb5
• Classification of Lifshitz invariant in multiband superconductors: an application to Leggett modes in the linear response regime in Kagome lattice models
• Existence of Hebel-Slichter peak in unconventional kagome superconductors
• AV${}_3$Sb${}_5$ kagome superconductors: a review with transport measurements
• Kagome materials $A$V${}_3$Sb${}_5$ ($A$=K,Rb,Cs): pairing symmetry and pressure-tuning studies
• Conventional Superconductivity in the Doped Kagome Superconductor Cs(V0.86Ta0.14)3Sb5 from Vortex Lattice Studies
• Probing the pairing symmetry in kagome superconductors based on the single-particle spectrum
• Observation of Anomalous Thermal Hall Effect in a Kagome Superconductor
• Observation of Fermi-surface-dependent anisotropic Cooper pairing in kagome superconductor CsV3Sb5
• Quantum-metric-induced giant and reversible nonreciprocal transport phenomena in chiral loop-current phases of kagome metals
• Low temperature phase transitions under CDW state in kagome metals AV3Sb5 (A=Cs,Rb,K): Significance of mix-type Fermi surface electron correlations
• Chiral pair density wave as a precursor of the pseudogap in kagomé superconductors
• Disorder-induced suppression of superconductivity in infinite-layer nickelates
• Interplay of superconductivity and charge-density-wave order in kagome materials
• Thermomodulated intrinsic Josephson effect in Kagome CsV3Sb5
• Local pairing versus bulk superconductivity intertwined by the charge density wave order in Cs(V${}_{1-x}$Ta${}_x$)${}_3$Sb${}_5$
• Impact of tiny Fermi pockets with extremely high mobility on the Hall anomaly in the kagome metal CsV${}_3$Sb${}_5$
• Impact of charge-density-wave pattern on the superconducting gap in V-based kagome superconductors
• Impact of Charge Density Waves on Superconductivity and Topological Properties in AV${}_3$Sb${}_5$ Kagome Superconductors
• Unified mechanism of charge-density-wave and high-$T_c$ superconductivity protected from oxygen vacancies in bilayer nickelates
• Calculated Unconventional Superconductivity via Charge Fluctuations in Kagome Metal CsV3Sb5
• Magnetoresistance hysteresis in the superconduting state of Kagome CsV${}_3$Sb${}_5$
• Two-dimensional superconductivity in a thick exfoliated kagome film
• Origin of switchable quasiparticle-interference chirality in loop-current phase of kagome metals measured by scanning-tunneling-microscopy
• Odd-parity quadrupole order and induced nonreciprocal transport in the kagome metal CsTi${}_3$Bi${}_5$ driven by quantum interference
• The possible frustrated superconductivity in the kagome superconductors
• Giant Impurity Effects on Charge Loop Current Order States in Kagome Metals
• Current-induced magnetoresistance hysteresis in the kagome superconductor CsV${}_3$Sb${}_5$
• Microscopic origin of period-four stripe charge-density-wave in kagome metal CsV${}_3$Sb${}_5$
• Strain-Tuned Nodal Superconductivity in the Charge-Ordered Kagome Metal CsV${}_3$Sb${}_5$