Enhanced superconductivity and mixed-dimensional behaviour in infinite-layer samarium nickelate thin films

Area of Science:

• Condensed Matter Physics
• Materials Science
• Superconductivity

Background:

• Rare-earth infinite-layer nickelates are a novel class of unconventional superconductors.
• Current synthesis efforts are primarily focused on early lanthanide compounds.

Purpose of the Study:

• To synthesize phase-pure samarium-based nickelate thin films.
• To investigate the relationship between structural properties and superconductivity.
• To explore the impact of rare-earth site engineering on superconducting behavior.

Main Methods:

• Thin film deposition on (LaAlO3)0.3(Sr2TaAlO6)0.7 (001) substrates.
• Co-doping with strontium to form Sm1-xSrxNiO2.
• Angle-dependent magnetoresistance measurements.
• Resonant inelastic X-ray scattering (RIXS).

Main Results:

• Successful synthesis of phase-pure samarium nickelate thin films.
• Achieved superconducting transition temperatures up to 32.5 K.
• Demonstrated a correlation between reduced c-axis parameter and increased critical temperature.
• Observed hybrid 2D/3D superconductivity with enhanced orbital coupling.
• Eu-doping induced a shift towards 3D superconductivity and negative magnetoresistance.

Conclusions:

• Samarium nickelates are promising candidates for high-temperature superconductivity.
• Structural engineering of the rare-earth site provides a pathway for optimizing superconducting properties.
• These findings offer design principles for future infinite-layer nickelate superconductors.