Luttinger Liquid Behavior in a Single-Layer Nickelate La1.4Sr0.6NiO4

Yinqi Hu; Yidian Li; Xian Du; Wenxuan Zhao; Kaiyi Zhai; Senyao Zhang; Jiawei Shao; Mingxin Mao; Houke Chen; Jieyi Liu; Donghui Lu; Makoto Hashimoto; Fangyuan Zhu; Zhengtai Liu; Dawei Shen; Yaobo Huang; Zhongkai Liu; D. Prabhakaran; Yanpeng Qi; Yilin Wang; Yulin Chen; Lexian Yang

arXiv · 2610.07656

Luttinger Liquid Behavior in a Single-Layer Nickelate La1.4Sr0.6NiO4

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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 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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Yinqi Hu, Yidian Li, Xian Du, Wenxuan Zhao, Kaiyi Zhai, Senyao Zhang, Jiawei Shao, Mingxin Mao, Houke Chen, Jieyi Liu, Donghui Lu, Makoto Hashimoto, Fangyuan Zhu, Zhengtai Liu, Dawei Shen, Yaobo Huang, Zhongkai Liu, D. Prabhakaran, Yanpeng Qi, Yilin Wang, Yulin Chen, Lexian Yang. 2026-10-06. Luttinger Liquid Behavior in a Single-Layer Nickelate La1.4Sr0.6NiO4. https://arxiv.org/abs/2610.07656

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