Unraveling p-type and n-type interfaces in Superconducting Infinite-Layer Nickelate thin films

Abstract

After decades of research, superconductivity was finally found in nickel-based analogs of superconducting cuprates, with infinite-layer (IL) structure. These results are so far restricted to thin films in the case of IL-nickelates. Therefore, the nature of the interface with the substrate, and how it couples with the thin film properties is still an open question. Here, using scanning transmission electron microscopy (STEM)- electron energy loss spectroscopy (EELS) and four-dimensional (4D)-STEM, a novel chemically sharp p-type interface is observed in a series of superconducting IL-praseodymium nickelate samples, and a comparative study is carried out with the previously reported n-type interface obtained in other samples. Both interfaces have strong differences, with the p-type interface being highly polar. In combination with ab-initio calculations, we find that the influence of the interface on the electronic structure is local, and does not extend beyond 2-3 unit cells into the thin film. This decouples the direct influence of the interface in driving the superconductivity, and indicates that the IL-nickelate thin films do not have a universal interface model. Insights into the spatial hole-distribution in SC samples, provided by monochromated EELS and total reflection-hard x-ray photoemission spectroscopy, suggest that this particular distribution might be directly influencing superconductivity.

References in corpus (25)

• Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials
• Advanced capabilities for materials modelling with Quantum ESPRESSO
• Why Some Interfaces Cannot be Sharp
• Superconducting Dome in Nd${}_{1-x}$Sr${}_x$NiO${}_2$ Infinite Layer Films
• A superconducting praseodymium nickelate with infinite layer structure
• Doping evolution of the Mott-Hubbard landscape in infinite-layer nickelates
• The Galaxies Beamline at SOLEIL Synchrotron: Inelastic X-ray Scattering and Photoelectron Spectroscopy in the Hard X-ray Range
• Absence of superconductivity in bulk Nd${}_{1-x}$Sr${}_x$NiO${}_2$
• Hybridization-controlled charge transfer and induced magnetism at correlated oxide interfaces
• Character of the "normal state" of the nickelate superconductors
• Charge density waves in infinite-layer NdNiO${}_2$ nickelates
• First-principles modeling of electrostatically doped perovskite systems
• Charge and spin order dichotomy in NdNiO${}_2$ driven by SrTiO${}_3$ capping layer
• Orbital and Spin Character of Doped Carriers in Infinite-Layer Nickelates
• Topotactic transformation of single-crystals: from perovskite to infinite-layer nickelates
• Fundamental difference in the electronic reconstruction of infinite-layer vs. perovskite neodymium nickelate films on SrTiO${}_3$(001)
• Reconstructing the polar interface of infinite-layer nickelate thin films
• Stability and electronic properties of the LaNiO${}_2$/SrTiO${}_3$ interface
• Charge distribution across capped and uncapped infinite-layer neodymium nickelate thin films
• Strain-induced enhancement of $T_c$ in infinite-layer Pr${}_{0.8}$Sr${}_{0.2}$NiO${}_2$ films
• Correlated interface electron gas in infinite-layer nickelate versus cuprate films on SrTiO${}_3$(001)
• Synthesis of infinite-layer nickelates and influence of the capping-layer on magnetotransport
• Superconductivity in freestanding infinite-layer nickelate membranes
• Synthesis of thin film infinite-layer nickelates by atomic hydrogen reduction: clarifying the role of the capping layer
• Emergent electronic landscapes in a novel valence-ordered nickelate with tri-component nickel coordination

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• Surfaces and interfaces of infinite-layer nickelates studied by dynamical mean-field theory
• Achieving superconductivity in infinite-layer nickelate thin films by aluminum sputtering deposition