Superconducting Lanthanum Nickel Oxides with Bilayered and Trilayered Crystal Structures

摘要

2023年，双层镍氧化物La₃Ni₂O₇在约14 GPa高压下被发现超导，临界温度近80 K，其结构与高温铜氧化物相似，随后又发现了三层La₄Ni₃O₁₀的超导性。这两种化合物属于Ruddlesden–Popper相，由NiO₂方晶格层与LaO岩盐层交替堆叠构成。当前研究主要沿三个方向展开：扩展化合物化学多样性、通过元素替代提升超导转变温度、以及阐明超导配对机制。然而，关键实验必须在高压下进行，这给机理研究带来困难，因此开发在更低压力甚至常压下表现超导的镍氧化物具有重要意义。本文综述了这些体系的现有知识，重点介绍已较为成熟的样品合成与表征方法，并简要概述其电子性质，旨在为后续材料探索和物理机制理解提供基础。

材料

• La₃Ni₂O₇
• La₄Ni₃O₁₀
• La₂NiO₄
• LaNiO₃
• La₅Ni₃O₁₁
• La₃Ni₂O₆

方法

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关键词

• ruddlesden popper phases
• nickelate superconductors
• high pressure superconductivity
• oxygen stoichiometry
• sample synthesis

亮点

• This review summarizes the present state of knowledge on superconducting lanthanum nickel oxides with bilayered and trilayered crystal structures.
• It emphasizes the importance of sample synthesis and characterization for progress in unconventional superconductors.

结论

• Superconductivity in La₃Ni₂O₇ and La₄Ni₃O₁₀ is likely unconventional and rooted in their unique electronic structures.
• Ke_y experiments must be performed under high pressure, posing difficulties for mechanistic studies.
• Developing nickel oxides that exhibit superconductivity at lower pressures is of great significance.
• Sample synthesis and characterization are already well established and often decisive for progress.

主要论断

• La₃Ni₂O₇ exhibits superconductivity under high pressure above 14 GPa with T_c up to 80 K.
  • 证据: Abstract,Full text: La₃Ni₂O₇ was discovered to exhibit superconductivity under pressures above approximately 14 GPa, with transition temperature reaching nearly 80 K.
• Superconductivity occurs in the tetragonal phase of the RP structure.
  • 证据: Full text,Section 2.2: Superconductivity occurs in the tetragonal phase, the ideal structure of the RP phase.
• Oxygen stoichiometry strongly affects superconductivity; excess oxygen and oxygen deficiency have different effects in La₃Ni₂O₇ and La₄Ni₃O₁₀.
  • 证据: Full text,Section 4.3.2: In La₃Ni₂O₇, oxygen excess shifts superconductivity to higher pressures and reduces T_c; in La₄Ni₃O₁₀, oxygen deficiency shifts superconductivity to higher pressures and lowers maximum T_c.

研究流程

本批次暂无数据。