The recent observation of superconductivity in [Formula: see text] has raised fundamental questions about the hierarchy of the underlying electronic structure. Calculations suggest that this system falls in the Mott-Hubbard regime, rather than the charge-transfer configuration of other nickel oxides and the superconducting cuprates. Here, we use state-of-the-art, locally resolved electron energy-loss spectroscopy to directly probe the Mott-Hubbard character of [Formula: see text] Upon doping, we observe emergent hybridization reminiscent of the Zhang-Rice singlet via the oxygen-projected states, modification of the Nd 5d states, and the systematic evolution of Ni 3d hybridization and filling. These experimental data provide direct evidence for the multiband electronic structure of the superconducting infinite-layer nickelates, particularly via the effects of hole doping on not only the oxygen but also nickel and rare-earth bands.
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http://dx.doi.org/10.1073/pnas.2007683118 | DOI Listing |
Commun Mater
January 2025
Physik-Institut, Universität Zürich, Zürich, Switzerland.
The discovery of unconventional superconductivity often triggers significant interest in associated electronic and structural symmetry breaking phenomena. For the infinite-layer nickelates, structural allotropes are investigated intensively. Here, using high-energy grazing-incidence x-ray diffraction, we demonstrate how in-situ temperature annealing of the infinite-layer nickelate PrNiO ( ≈ 0) induces a giant superlattice structure.
View Article and Find Full Text PDFPhys Rev Lett
November 2024
National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, New York 11973, USA.
Superconductivity in infinite layer nickelates Nd_{1-x}Sr_{x}NiO_{2} has so far been achieved only in thin films, raising questions on the role of substrates and interfaces. Given the challenges associated with their synthesis it is imperative to identify their intrinsic properties. We use resonant inelastic x-ray scattering to investigate the influence of the SrTiO_{3} capping layer on the excitations of Nd_{1-x}Sr_{x}NiO_{2} (x=0 and 0.
View Article and Find Full Text PDFNat Commun
November 2024
National Synchrotron Radiation Laboratory, School of Nuclear Science and Technology, University of Science and Technology of China, Hefei, China.
Recent observations of superconductivity in infinite-layer nickelates offer insights into high-temperature superconductivity mechanisms. However, defects and dislocations in doped films complicate the realization of superconductivity, limiting current research to superconducting nickelate heterostructures. The lack of research on superconductivity in superlattices composed of ultrathin nickelates severely impedes not only the exploration of the interface effect on superconductivity, but also the utilization of heterostructure engineering for exploring higher superconducting temperature T.
View Article and Find Full Text PDFNat Commun
November 2024
High Field Magnet Laboratory (HFML-FELIX) and Institute for Molecules and Materials, Radboud University, Toernooiveld 7, 6525 ED, Nijmegen, Netherlands.
Phys Rev Lett
September 2024
Department of Physics, University of California at Berkeley, Berkeley, California 94720, USA.
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