Layer Architecture Shapes Electronic, Magnetic, and Lattice Interactions in Ruddlesden-Popper Nickelates

W. He; X. Guo; X. Luo; J. Thomas; J. Sears; Sophia F. R. TenHuisen; Ziqiang Guan; Xinglong Chen; D. A. Dahlbom; B. Zager; J. Pelliciari; Yi-Feng Zhao; H. LaBollita; Hong Zheng; M. K. Lajer; J. F. Mitchell; V. Bisogni; A. S. Botana; M. Mitrano; S. Johnston; M. P. M. Dean

arXiv · 2609.04532

Layer Architecture Shapes Electronic, Magnetic, and Lattice Interactions in Ruddlesden-Popper Nickelates

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Abstract

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.

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W. He, X. Guo, X. Luo, J. Thomas, J. Sears, Sophia F. R. TenHuisen, Ziqiang Guan, Xinglong Chen, D. A. Dahlbom, B. Zager, J. Pelliciari, Yi-Feng Zhao, H. LaBollita, Hong Zheng, M. K. Lajer, J. F. Mitchell, V. Bisogni, A. S. Botana, M. Mitrano, S. Johnston, M. P. M. Dean. 2026-09-03. Layer Architecture Shapes Electronic, Magnetic, and Lattice Interactions in Ruddlesden-Popper Nickelates. https://arxiv.org/abs/2609.04532

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