发表机构
Tsinghua University; Yale University; University of Oxford; Diamond Light Source; SLAC National Accelerator Laboratory; Shanghai Advanced Research Institute, Chinese Academy of Sciences; University of Science and Technology of China; ShanghaiTech University（清华大学; 耶鲁大学; 牛津大学; 钻石光源; 斯坦福直线加速器中心; 中国科学院上海高等研究院; 中国科学技术大学; 上海科技大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过ARPES和理论计算发现单层镍酸盐La1.4Sr0.6NiO4呈现准一维电子结构，表现出Luttinger液体非费米液体行为，为理解多层镍酸盐物理提供新视角。
AI 中文摘要
双层和三层镍酸盐中高温超导性的发现激发了人们对Ruddlesden-Popper镍酸盐的浓厚兴趣；然而，NiO2层的基本性质仍被层间耦合所掩盖。因此，研究其单层对应物的电子性质以隔离NiO层的本征物理至关重要。在本工作中，我们利用高分辨率角分辨光电子能谱（ARPES）和理论计算对单层镍酸盐La1.4Sr0.6NiO4进行了系统研究。我们揭示了强电子关联效应，表现为能带色散中的高能扭结和显著的轨道依赖的能带重整化。有趣的是，我们观察到一种准一维电子结构，其特征是沿对角动量方向的直线费米面片。这种方形费米面拓扑促进了与Luttinger液体模型一致的非费米液体行为，这由幂律谱函数、稳健的温度标度以及自旋-电荷分离的观测所证实。因此，我们的结果不仅揭示了在本质上准二维的镍酸盐中因意外维度降低而涌现的奇异Luttinger液体行为，而且为理解多层镍酸盐中有趣的物理提供了新视角。
英文摘要
The discovery of high-temperature superconductivity in bilayer and trilayer nickelates has spurred intense interest in the Ruddlesden-Popper nickelates; yet the fundamental properties of the NiO2 layer remain obscured by interlayer coupling. It is therefore imperative to investigate the electronic properties of their single-layer counterpart to isolate the intrinsic physics of the NiO layer. In this work, we present a systematic study of the single-layer nickelate La1.4Sr0.6NiO4 using high-resolution angle-resolved photoemission spectroscopy (ARPES) and theoretical calculations. We reveal strong electron correlation effects, manifested by high-energy kinks in band dispersions and a pronounced orbital-dependent band renormalization. Interestingly, we observe a quasi-one-dimensional electronic structure characterized by straight Fermi surface sheets along the diagonal momentum directions. Such square Fermi surface topology facilitates non-Fermi liquid behavior consistent with the Luttinger liquid model, as evidenced by the power-law spectral function, robust temperature scaling, and the observation of spin-charge separation. Our results therefore not only unveil an exotic Luttinger liquid behavior emerging from the unexpected dimensional reduction in an intrinsically quasi-two-dimensional nickelate but also provide a new perspective for understanding the intriguing physics in multilayer nickelates.
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