Chen Xiaoyang, Choi Jaewon, Jiang Zhicheng, Mei Jiong, Jiang Kun, Li Jie, Agrestini Stefano, Garcia-Fernandez Mirian, Sun Hualei, Huang Xing, Shen Dawei, Wang Meng, Hu Jiangping, Lu Yi, Zhou Ke-Jin, Feng Donglai
State Key Laboratory of Surface Physics, Department of Physics, and Advanced Materials Laboratory, Fudan University, Shanghai, China.
Diamond Light Source, Didcot, UK.
Nat Commun. 2024 Nov 6;15(1):9597. doi: 10.1038/s41467-024-53863-5.
High-temperature superconductivity was discovered in the pressurized nickelate LaNiO which has a unique bilayer structure and mixed valence state of nickel. The properties at ambient pressure contain crucial information of the fundamental interactions and bosons mediating superconducting pairing. Here, using X-ray absorption spectroscopy and resonant inelastic X-ray scattering, we identified that Ni 3 , Ni 3 , and ligand oxygen 2p orbitals dominate the low-energy physics with a small charge-transfer energy. Well-defined optical-like magnetic excitations soften into quasi-static spin-density-wave ordering, evidencing the strong electronic correlation and rich magnetic properties. Based on an effective Heisenberg spin model, we extract a much stronger inter-layer effective magnetic superexchange than the intra-layer ones and propose two viable magnetic structures. Our findings emphasize that the Ni 3 orbital bonding within the bilayer induces novel electronic and magnetic excitations, setting the stage for further exploration of LaNiO superconductor.
在具有独特双层结构和镍混合价态的加压镍酸盐LaNiO中发现了高温超导性。常压下的性质包含了基本相互作用和介导超导配对的玻色子的关键信息。在这里，我们使用X射线吸收光谱和共振非弹性X射线散射，确定了Ni 3 、Ni 3 和配体氧2p轨道以小的电荷转移能量主导低能物理。定义明确的类光学磁激发软化为准静态自旋密度波有序，证明了强电子相关性和丰富的磁性。基于有效的海森堡自旋模型，我们提取出比层内有效磁超交换更强的层间有效磁超交换，并提出了两种可行的磁结构。我们的发现强调双层内的Ni 3 轨道键合诱导了新颖的电子和磁激发，为进一步探索LaNiO超导体奠定了基础。
