Superconductivity in PrNiO₂ Infinite-Layer Nickelates.

Area of Science:

• Materials Science
• Condensed Matter Physics
• Superconductivity

Background:

• Infinite-layer nickelates are a novel class of materials with potential for high-temperature superconductivity.
• Existing research suggests a dome-shaped phase diagram dependent on chemical doping, similar to cuprates.

Purpose of the Study:

• To investigate superconductivity in undoped infinite-layer PrNiO2 thin films.
• To characterize the structural and electronic properties of these films.
• To determine the role of chemical doping in achieving superconductivity.

Main Methods:

• Growth of high-quality undoped PrNiO2 thin films on SrTiO3 substrates.
• Scanning transmission electron microscopy (STEM) for structural analysis.
• X-ray absorption spectroscopy (XAS) for electronic state characterization.
• Resonant inelastic X-ray scattering (RIXS) for magnetic excitation analysis.

Main Results:

• Demonstrated a highly reproducible superconducting state in undoped PrNiO2 films.
• STEM confirmed a coherent infinite-layer phase with high structural quality and minimal defects.
• XAS revealed preferential hole occupation of Ni 3d orbitals in a square planar geometry.
• RIXS detected sharp magnon excitations, resonant with Ni 1+ absorption peaks.

Conclusions:

• Infinite-layer nickelate thin films can be superconducting without chemical doping when properly stabilized.
• The findings suggest intrinsic superconductivity in the undoped state, challenging doping-centric models.
• This work opens new avenues for exploring superconductivity in nickelate systems.