Source capture
Authors Mathieu Flavenot, Hoshang Sahib, Jérôme Robert, Marc Lenertz, Gilles Versini, Laurent Schlur, Alexandre Gloter, Nathalie Viart, Daniele Preziosi
arXiv / Publisher http://arxiv.org/abs/2604.09807v1
PDF https://arxiv.org/pdf/2604.09807v1
Relevance score 5.875
Primary category Not available in this batch.
Published Not available in this batch.
Research paradigm Experimental
Sample form Thin Film

Summary

This study presents a detailed structural analysis of epitaxial La3Ni2O7-δ thin films using scanning transmission electron microscopy combined with electron energy loss spectroscopy. The films were prepared on SrLaAlO4 substrates via pulsed laser deposition and exhibited significantly distinct superconducting properties after different ozone annealing treatments. It was found that the stabilization of the superconducting phase is closely related to oxygen stoichiometry uniformity, epitaxial strain, and specific stacking structural motifs such as bilayers and polytypes. By correlating the rich morphology of stacking polytypes with transport behavior, a theoretical framework for understanding metastable superconducting phases in bilayer nickelate thin films was established. The results reveal the critical roles of oxygen content, lattice strain, and structural ordering in achieving ambient-pressure superconductivity, providing a clear pathway for designing new nickel-based superconducting materials.

Materials

Methods

Keywords

Highlights

  • The rich morphology of stacking polytypes is correlated with transport behavior.
  • The study provides a theoretical framework for understanding metastable superconducting phases in bilayer nickelate thin films.

Conclusions

  • Stabilization of the superconducting phase is closely related to oxygen stoichiometry uniformity, epitaxial strain, and specific stacking structural motifs such as bilayers and polytypes.
  • Oxygen content, lattice strain, and structural ordering are critical for achieving ambient-pressure superconductivity.

Main claims

  • The stabilization of superconductivity in La3Ni2O7 thin films depends critically on oxygen stoichiometry uniformity and the presence of specific stacking polytypes
    • Evidence: STEM-EELS shows that samples with better oxygen homogeneity and fewer stacking faults exhibit higher Tc and narrower transitions; O K pre-edge intensity correlates with metallic behavior

Workflow

  • Thin film growth and ozone annealing — Oxygen stoichiometry and stacking order are key
    • Materials: La3Ni2O7-δ films on SLAO
    • Methods: PLD; Ozone annealing
    • Observations: XRD, STEM identify polytypes
  • Spectroscopic and transport characterization — Oxygen uniformity and structural ordering determine superconductivity
    • Materials: STEM-EELS; Transport
    • Methods: EELS O K-edge and Ni L-edge; Resistivity measurements
    • Observations: Correlation between O K pre-peak intensity and superconducting properties; Polytypes affect Tc