Daily Overview: Today’s highlights focus on the optimization of Ruddlesden-Popper nickelate thin film preparation and the discovery of unconventional superconductivity. In [1], the research team successfully fabricated phase-pure, high-quality Ln₃Ni₂O₇ thin films using giant oxidative atomic layer epitaxy, and systematically revealed the decisive role of four key factors—cation stoichiometry, atomic layer coverage, oxygen content, and interface reconstruction—on superconducting performance. The optimized films exhibited an onset transition temperature of up to 50 K, providing important guidance for the epitaxial growth of high-quality nickel-based superconducting thin films. In [2], through electrical transport measurements of (La, Pr, Sm)₃Ni₂O₇ bilayer nickelate thin films, time-reversal symmetry breaking superconductivity accompanied by electronic glass behavior was discovered for the first time, including features such as anomalous magnetoresistance hysteresis, nonreciprocal current-voltage response, and logarithmic slow relaxation. This finding offers groundbreaking phenomenological evidence and a conceptual framework for understanding the mechanism of nickel-based high-temperature superconductivity. arXiv submission processing window: 2026-03-05 00:00 to 2026-03-05 00:00 UTC.
1. Preparation and optimization of high-temperature superconducting Ruddlesden-Popper nickelate thin films
- Relevance Score:
5.5612 - Authors: Wei Lv, Zihao Nie, Heng Wang, Haoliang Huang, Guangdi Zhou, Qikun Xue, Zhuoyu Chen
- Affiliations: Tsinghua University, Southern University of Science and Technology, Quantum Science Center of Guangdong-Hong Kong-Macao Greater Bay Area
- Link: https://arxiv.org/abs/2508.18107
- Paper page: Preparation and optimization of high-temperature superconducting Ruddlesden-Popper nickelate thin films
Summary: This study successfully fabricated phase-pure, high-quality Ruddlesden-Popper nickelate Ln₃Ni₂O₇ thin films on LaAlO₃ and SrLaAlO₄ substrates using the giant oxidation atomic layer epitaxy (GAE) method. Films grown under strongly oxidizing ozone atmosphere exhibited superconductivity without requiring post-annealing, with optimized Ln₃Ni₂O₇/SrLaAlO₄ films achieving an onset transition temperature (Tc,onset) as high as 50 K. Systematic investigation identified four key factors governing film crystallinity and superconducting performance: precise control of cation stoichiometry suppresses secondary phase formation; complete atomic layer-by-layer coverage combined with optimized interface reconstruction reduces stacking faults; accurate regulation of oxygen content is essential for achieving a single superconducting transition and high Tc,onset. The study also revealed that deviation in cation stoichiometry leads to the formation of Ni-rich or Ni-deficient secondary phases, inducing metal-insulator transitions or highly insulating behavior, respectively, while deviations in atomic layer coverage (e.g., 101.5%) still allow superconductivity but introduce residual resistance. Interface reconstruction, such as predisposing half-unit-cell Ln₂NiO₄ or annealing the SrLaAlO₄ substrate, significantly improves film crystallinity. These findings provide important guidance for the layer-by-layer epitaxial growth of high-quality oxide high-temperature superconducting thin films.
2. Time-reversal symmetry breaking superconductivity with electronic glass in nickelate (La, Pr, Sm)3Ni2O7 films
- Relevance Score:
5.5543 - Authors: Haoran Ji, Zheyuan Xie, Yaqi Chen, Guangdi Zhou, Longxin Pan, Heng Wang, Haoliang Huang, Jun Ge, Yi Liu, Guang-Ming Zhang, Ziqiang Wang, Qi-Kun Xue, Zhuoyu Chen, Jian Wang
- Affiliations: Tsinghua University, Hefei National Laboratory, Peking University, Boston College, Collaborative Innovation Center of Quantum Matter, Southern University of Science and Technology, ShanghaiTech University, Renmin University of China, Quantum Science Center of Guangdong-Hong Kong-Macao Greater Bay Area
- Link: https://arxiv.org/abs/2508.16412
- Paper page: Time-reversal symmetry breaking superconductivity with electronic glass in nickelate (La, Pr, Sm)₃Ni₂O₇ films
Summary: The research team conducted electrical transport measurements on (La, Pr, Sm)₃Ni₂O₇ double-layer nickelate thin films and discovered a time-reversal symmetry breaking superconducting state accompanied by electronic glass behavior. This superconducting state emerges in the low-temperature regime near zero resistance, exhibiting three prominent features: first, an unconventional magnetoresistance hysteresis that directly evidences time-reversal symmetry breaking and remains robust under different magnetic field orientations, fundamentally distinct from vortex pinning or long-range magnetic order; continuous oxygen reduction simultaneously weakens both superconductivity and the hysteresis, revealing their connection to specific Ni 3d electronic orbitals. Second, the current–voltage response demonstrates magnetic history dependence and non-reciprocity under zero field, further confirming spontaneous intrinsic time-reversal symmetry breaking. Third, the resistance exhibits slow logarithmic relaxation after removing the magnetic field, a hallmark of glassy dynamics. These phenomena reveal for the first time in nickel-based superconductors a superconducting state that simultaneously possesses spontaneous time-reversal symmetry breaking and intrinsic glassy characteristics, providing significant phenomenological and conceptual breakthroughs for understanding the mechanism of high-temperature superconductivity.