强相关的过渡金属氧化物因其各种奇异现象而广为人知。例如,稀土镍酸盐,例如LaNiO3,它们的电子之间具有紧密的互连,spin,和晶格自由度。通过将它们配对在混合异质结构中,可以进一步增强它们的性能,这可能导致隐藏阶段和紧急现象。一个重要的例子是LaNiO3/LaTiO3超晶格,观察到从LaTiO3到LaNiO3的层间电子转移,导致高自旋态。然而,到目前为止,尚未观察到与这种高自旋态相关的磁性秩序的宏观出现。这里,通过使用μ子自旋旋转,x射线吸收,和共振非弹性X射线散射,提出了在LaNiO3/LaTiO3界面处具有高磁振子能量和交换相互作用的新兴反铁磁秩序的直接证据。由于磁性是纯粹的界面,单个LaNiO3/LaTiO3界面基本上可以表现为原子级薄的强相关准2D反铁磁体,有可能允许其技术应用于先进的自旋电子器件。此外,它具有很强的准2D磁相关性,轨道极化的平面配体孔,分层超晶格设计使其电子,磁性,晶格构型类似于超导铜酸盐和镍酸盐的前体状态,但以S→1自旋状态代替。
Strongly-correlated transition-metal oxides are widely known for their various exotic phenomena. This is exemplified by rare-earth nickelates such as LaNiO3, which possess intimate interconnections between their electronic, spin, and lattice degrees of freedom. Their properties can be further enhanced by pairing them in hybrid heterostructures, which can lead to hidden phases and emergent phenomena. An important example is the LaNiO3/LaTiO3 superlattice, where an interlayer electron transfer has been observed from LaTiO3 into LaNiO3 leading to a high-spin state. However, macroscopic emergence of magnetic order associated with this high-spin state has so far not been observed. Here, by using muon spin rotation, x-ray absorption, and resonant inelastic x-ray scattering, direct evidence of an emergent antiferromagnetic order with high magnon energy and exchange interactions at the LaNiO3/LaTiO3 interface is presented. As the magnetism is purely interfacial, a single LaNiO3/LaTiO3 interface can essentially behave as an atomically thin strongly-correlated quasi-2D antiferromagnet, potentially allowing its technological utilization in advanced spintronic devices. Furthermore, its strong quasi-2D magnetic correlations, orbitally-polarized planar ligand holes, and layered superlattice design make its electronic, magnetic, and lattice configurations resemble the precursor states of superconducting cuprates and nickelates, but with an S→1 spin state instead.