Phase-sensitive evidence for pair density waves in a kagome superconductor

Abstract

Pair density wave (PDW) exhibits periodic amplitude and sign modulations of the superconducting order parameter. Such a pairing state has long been proposed to be highly sensitive to nonmagnetic scattering, but its experimental realization remains elusive. Here we discover a nonmagnetic PDW-breaking effect in a kagome superconductor, using designer atomic nonmagnetic impurities and high-precision scanning tunneling microscopy (STM) at a base temperature of 30mK. We detect 2x2 pair density modulations by Josephson STM with a superconducting tip and 2x2 pairing gap modulations by normal STM. We find that the pairing modulations in both cases are substantially suppressed upon doping the kagome lattice with dilute isovalent nonmagnetic impurities, whereas the charge order and uniform superconductivity remain robust. We further identify the correlation between atomic dopants and the local suppression of PDW. We attribute these findings to a nonmagnetic pair-breaking effect, arising from the phase modulation of PDW in the kagome d-orbital. Taken together with its signatures in other state-of-the-art spectroscopy and transport measurements linked by theory, our findings support the ground state of the kagome superconductor as a correlated topological phase with superconducting loop currents.

15 pages, 5 figures; Supplementary Material included; updated to match the published version

References in corpus (48)

• Theory of Intertwined Orders in High Temperature Superconductors
• Discovery of microscopic electronic inhomogeneity in the high-Tc superconductor Bi2Sr2CaCu2O8+x
• 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
• Time-reversal symmetry-breaking charge order in a kagome superconductor
• Superconductivity in the ${\mathbb{Z}}_2$ kagome metal KV${}_3$Sb${}_5$
• The Physics of Pair Density Waves
• Detection of a Cooper-Pair Density Wave in Bi${}_2$Sr${}_2$CaCu${}_2$O${}_{8+x}$
• Chiral flux phase in the Kagome superconductor AV${}_3$Sb${}_5$
• Analysis of Charge Order in the Kagome Metal $A$V${}_3$Sb${}_5$ ($A=$K,Rb,Cs)
• Electronic instabilities of kagome metals: saddle points and Landau theory
• Complex charge density waves at Van Hove singularity on hexagonal lattices: Haldane-model phase diagram and potential realization in kagome metals ${\text{AV}}_3{\text{Sb}}_5$
• Multiband superconductivity with sign-preserving order parameter in kagome superconductor CsV3Sb5
• Theory of the striped superconductor
• Tunable nodal kagome superconductivity in charge ordered RbV3Sb5
• Discovery of a Cooper-Pair Density Wave State in a Transition-Metal Dichalcogenide
• Nodeless electron pairing in CsV${}_3$Sb${}_5$-derived kagome superconductors
• Mechanism of exotic density-wave and beyond-Migdal unconventional superconductivity in kagome metal AV3Sb5 (A=K, Rb, Cs)
• Visualizing the Energy-gap Modulations of the Cuprate Pair Density Wave State
• Chern Fermi pocket, topological pair density wave, and charge-4e and charge-6e superconductivity in kagome superconductors
• Detection of a Pair Density Wave State in UTe${}_2$
• Superconducting diode effect and interference patterns in Kagome CsV3Sb5
• Fluctuation Dominated Josephson Tunneling with a Scanning Tunneling Microscope
• Loop currents in $A$V${}_3$Sb${}_5$ kagome metals: multipolar and toroidal magnetic orders
• Discovery of a pair density wave state in a monolayer high-Tc iron-based superconductor
• Chiral kagome superconductivity modulations with residual Fermi arcs in KV3Sb5 and CsV3Sb5
• Smectic Pair Density Wave Order in EuRbFe4As4
• Charge-loop current order and Z3 nematicity mediated by bond-order fluctuations in kagome metal AV3Sb5 (A=Cs,Rb,K)
• Fulde-Ferrell-Larkin-Ovchinnikov state in disordered s-wave superconductors
• Interplay between Pair Density Wave and a Nested Fermi Surface
• Evidence chain for time-reversal symmetry-breaking kagome superconductivity
• Identification of a Nematic Pair Density Wave State in Bi2Sr2CaCu2O8+x
• Sublattice modulated superconductivity in the Kagome Hubbard model
• Unconventional gapping behavior in a kagome superconductor
• Directly visualizing nematic superconductivity driven by the pair density wave in NbSe${}_2$
• Chiral pair density waves with residual Fermi arcs in RbV3Sb5
• Self-consistent theory of $2\times 2$ pair density waves in kagome superconductors
• Theory of charge-6e condensed phase in Kagome lattice superconductors
• Interplay between Chiral Charge Density Wave and Superconductivity in Kagome Superconductors: A Self-consistent Theoretical Analysis
• Observation of Anomalous Thermal Hall Effect in a Kagome Superconductor
• Pair-breaking scattering interference as a mechanism for superconducting gap modulation
• 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${}_5$
• Chiral pair density wave as a precursor of the pseudogap in kagomé superconductors
• Interplay of superconductivity and charge-density-wave order in kagome materials
• Switchable chiral 2x2 pair density wave in pure CsV3Sb5
• Origin of switchable quasiparticle-interference chirality in loop-current phase of kagome metals measured by scanning-tunneling-microscopy

Cited by in corpus (1)

• Visualizing Pair-breaking Scattering Interference in Bulk FeSe