Low-energy electrodynamics of infinite-layer nickelates: evidence for d-wave superconductivity in the dirty limit

Abstract

The discovery of superconductivity in infinite-layer nickelates establishes a new category of unconventional superconductors that share structural and electronic similarities with cuprates. Despite exciting advances, such as the establishment of a cuprate-like phase diagram and the observation of charge order and short-range antiferromagnetic fluctuation, the key issues of superconducting pairing symmetry, gap amplitude, and superconducting fluctuation remain elusive. In this work, we utilize static and ultrafast terahertz spectroscopy to address these outstanding problems. We demonstrate that the equilibrium terahertz conductivity and nonequilibrium terahertz responses of an optimally Sr-doped nickelate film ($T_c$ = 17 K) are in line with the electrodynamics of $d$-wave superconductivity in the dirty limit. The gap-to-$T_c$ ratio 2$\Delta /k_{\mathrm{B}}{T}_{\mathrm{c}}$ is extracted to be 3.4, indicating the superconductivity falls in the weak-coupling regime. In addition, we observed significant superconducting fluctuation near $T_{\mathrm{c}}$, while it does not extend into the deep normal state as optimally hole-doped cuprates. Our result highlights a new $d$-wave system which closely resembles the electron-doped cuprates, expanding the family of unconventional superconductivity in oxides.

8 pages, 4 figures

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Cited by in corpus (20)

• Ambient-pressure superconductivity onset above 40 K in bilayer nickelate ultrathin films
• Electronic Structure of Superconducting Infinite-Layer Lanthanum Nickelates
• Ultrafast Dynamics of Bilayer and Trilayer Nickelate Superconductors
• Recent progress in nickelate superconductors
• Electronic structure of Ruddlesden-Popper nickelates: strain to mimic the effects pressure
• Superconductivity in freestanding infinite-layer nickelate membranes
• On the origin of topotactic reduction effect for superconductivity in infinite-layer nickelates
• Superconductivity in the parent infinite-layer nickelate NdNiO${}_2$
• Multi-Dimensional Coherent Spectroscopy of Light-Driven States and their Collective Modes in Multi-Band Superconductors
• Cuprate Twistronics for Quantum Hardware
• Intertwined charge and spin instability of La${}_3$Ni${}_2$O${}_7$
• Charge Stripe Manipulation of Superconducting Pairing Symmetry Transition
• Disorder-dependent superconducting pairing symmetry in doped graphene
• Disorder-induced suppression of superconductivity in infinite-layer nickelates
• Topotactical Hydrogen Induced Single-Band $d$-wave Superconductivity in La${}_2$NiO${}_4$
• Lattice dynamics of the infinite-layer nickelate LaNiO${}_2$
• Pressure effects on the electronic structure and magnetic properties of infinite-layer nickelates
• Re-entrant unconventional superconductivity induced by rare-earth substitution in Nd1-xEuxNiO2 thin films
• Unconventional Pressure Dependent Interorbital and Interlayer Doping in Superconducting Nickelates
• Raman response in superconducting multiorbital systems with application to nickelates