发表机构
Brookhaven National Laboratory; Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory; The University of Tennessee, Knoxville; Harvard University; Argonne National Laboratory; Oak Ridge National Laboratory; National Synchrotron Light Source II, Brookhaven National Laboratory（布鲁克海文国家实验室; 斯坦福物质与能源科学研究所，SLAC国家加速器实验室; 田纳西大学诺克斯维尔分校; 哈佛大学; 阿贡国家实验室; 橡树岭国家实验室; 国家同步光源二期，布鲁克海文国家实验室）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文通过RIXS对比研究不同层结构的Ruddlesden-Popper镍酸盐，揭示层结构对其电子、磁与晶格相互作用的影响，为相关超导理论模型提供关键实验约束。
AI 中文摘要
Ruddlesden-Popper镍酸盐中超导电性的发现提出了一个核心问题：层结构如何塑造与配对相关的电子、磁和晶格相互作用？本文利用Ni L3边和O K边的共振非弹性X射线散射（RIXS），对La3Ni2O7的两种多晶型——交替单层-三层结构（LNO-1313）和双层结构（LNO-2222）——以及相关的三层化合物La4Ni3O10开展了详细的对比研究。研究发现，LNO-1313和La4Ni3O10具有极为相似的电子、磁和晶格激发特征，而双层结构LNO-2222则表现出截然不同的特征。与LNO-2222相比，LNO-1313和La4Ni3O10的轨道极化更弱、3d8L特性增强、面外磁交换尺度更小，且电子-声子耦合（EPC）更强。在有效局域矩框架内，纠缠二聚体情景可自然描述由强反铁磁层间耦合产生的自旋激发；相较于传统自旋波理论，该情景的优势在双层结构LNO-2222中最为明显，此处层间耦合主导了层内相互作用。这些发现为未来研究这类层状镍酸盐中超导电性相关低能物理的理论模型提供了关键的实验约束。
英文摘要
The discovery of superconductivity in Ruddlesden-Popper nickelates has raised a central question: how does layer architecture shape the electronic, magnetic, and lattice interactions relevant to pairing? Here, we report a detailed comparative study of the two polymorphs of La3Ni2O7--the alternating monolayer-trilayer (LNO-1313) and bilayer (LNO-2222) structures--and the related trilayer compound La4Ni3O10, using both Ni L3- and O K-edge RIXS. We find that LNO-1313 and La4Ni3O10 share strikingly similar electronic, magnetic, and lattice excitations, whereas bilayer LNO-2222 exhibits distinct features. Compared to LNO-2222, LNO-1313 and La4Ni3O10 have weaker orbital polarization, enhanced 3d8L character, a reduced out-of-plane magnetic-exchange scale, and stronger EPC. Within an effective local-moment framework, an entangled-dimer scenario provides a natural description of the spin excitations generated by strong antiferromagnetic interlayer coupling. Its advantage over conventional spin-wave theory is clearest in bilayer LNO-2222, where the interlayer coupling dominates the intralayer interactions. These findings provide critical experimental constraints for future theoretical models for the low-energy physics relevant to superconductivity in these layered nickelates.
Comments10 pages, 5 figures, not including references and additional material
