Nodeless electron pairing in CsV${}_3$Sb${}_5$-derived kagome superconductors

Abstract

The newly discovered kagome superconductors represent a promising platform for investigating the interplay between band topology, electronic order, and lattice geometry. Despite extensive research efforts on this system, the nature of the superconducting ground state remains elusive. In particular, consensus on the electron pairing symmetry has not been achieved so far, in part owing to the lack of a momentum-resolved measurement of the superconducting gap structure. Here we report the direct observation of a nodeless, nearly isotropic, and orbital-independent superconducting gap in the momentum space of two exemplary CsV${}_3$Sb${}_5$-derived kagome superconductors -- Cs(V${}_{0.93}$Nb${}_{0.07}$)${}_3$Sb${}_5$ and Cs(V${}_{0.86}$Ta${}_{0.14}$)${}_3$Sb${}_5$, using ultrahigh resolution and low-temperature angle-resolved photoemission spectroscopy (ARPES). Remarkably, such a gap structure is robust to the appearance or absence of charge order in the normal state, tuned by isovalent Nb/Ta substitutions of V. Moreover, we observe a signature of the time-reversal symmetry (TRS) breaking inside the superconducting state, which extends the previous observation of TRS-breaking CDW in the kagome lattice. Our comprehensive characterizations of the superconducting state provide indispensable information on the electron pairing of kagome superconductors, and advance our understanding of unconventional superconductivity and intertwined electronic orders.

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Cited by in corpus (55)

• AV${}_3$Sb${}_5$ Kagome Superconductors: Progress and Future Directions
• Superconducting diode effect and interference patterns in Kagome CsV3Sb5
• Superconductivity emerging from density-wave-like order in a correlated kagome metal
• Topological thermal transport
• Evidence chain for time-reversal symmetry-breaking kagome superconductivity
• 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
• Superconducting, topological and transport properties of kagome metals CsTi${}_3$Bi${}_5$ and RbTi${}_3$Bi${}_5$
• Superconductivity from Orbital-Selective Electron-Phonon Coupling in $A{\mathrm{V}}_3{\mathrm{Sb}}_5$
• Emergent superconductivity and pair density wave at antiphase boundaries of charge density wave order in kagome metals
• Unconventional gapping behavior in a kagome superconductor
• Kagome metals
• Phenomenology of bond and flux orders in kagome metals
• Evolution of charge density waves from three-dimensional to quasi-two-dimensional in Kagome superconductors Cs(V${}_{1-x}{M}_x$)${}_3$Sb${}_5$ ($M$ = Nb, Ta)
• Chiral-Flux-Phase-Based Topological Superconductivity in Kagome Systems with Mixed Edge Chiralities
• Evidence of a distinct collective mode in Kagome superconductors
• Uniaxial strain tuning of charge modulation and singularity in a kagome superconductor
• Chemical Rules for Stacked Kagome and Honeycomb Topological Semimetals
• Dynamical decoding of the competition between charge density waves in a kagome superconductor
• Existence of Hebel-Slichter peak in unconventional kagome superconductors
• AV${}_3$Sb${}_5$ kagome superconductors: a review with transport measurements
• Perspective: imaging atomic step geometry to determine surface terminations of kagome materials and beyond
• Revealing the orbital origins of exotic electronic states with Ti substitution in kagome superconductor CsV3Sb5
• Tunability of charge density wave in a magnetic kagome metal
• Interplay between Chiral Charge Density Wave and Superconductivity in Kagome Superconductors: A Self-consistent Theoretical Analysis
• Tunable vortex bound states in multiband CsV3Sb5-derived kagome superconductors
• 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
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• Observation of Fermi-surface-dependent anisotropic Cooper pairing in kagome superconductor CsV3Sb5
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• Microscopic study of the impurity effect in the kagome superconductor La(Ru${}_{1-x}$Fe${}_x$)${}_3$Si${}_2$
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• Inversion and Tunability of Van Hove Singularities in $A$V${}_3$Sb${}_5$ ($A$ = K, Rb, and Cs) kagome metals
• Impact of Charge Density Waves on Superconductivity and Topological Properties in AV${}_3$Sb${}_5$ Kagome Superconductors
• Magnetoresistance hysteresis in the superconduting state of Kagome CsV${}_3$Sb${}_5$
• Switchable chiral 2x2 pair density wave in pure CsV3Sb5
• Stability Frontiers and Mixed-dimensional physics in the Kagome Intermetallics Ln3ScBi5 (Ln = La-Nd, Sm)
• Electronic inhomogeneity in Cs- and Sb-terminated surfaces of CsV${}_3$Sb${}_5$ probed by scanning photoemission spectromicroscopy
• Recent progress in quantum spin liquids, fractional magnetization plateaus, and unconventional superconductivity in kagome lattices
• Phase-sensitive evidence for pair density waves in a kagome superconductor
• Time-Resolved Photoemission Spectroscopy of Quantum Materials Using High Harmonic Generation: Probing Electron-Phonon Interactions and Non-Equilibrium Dynamics
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