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arXiv · 2511.09460

Impact of Electron Correlations on Infinite-Layer Cuprates and Nickelates

Xunyang Hong·Yuetong Wu·Ying Chan·Sze Tung Li·I. Biało·L. Martinelli·A. Drewanowski·Qiang Gao·Xiaolin Ren·Xingjiang Zhou·Zhihai Zhu·A. Galdi·D. G. Schlom·K. M. Shen·J. Choi·M. Garcia Fernandez·Ke-Jin Zhou·N. B. Brookes·H. M. Rønnow·Qisi Wang·J. Chang
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Abstract

Optimization of unconventional superconductivity involves a balance of interaction strengths. Precise determination of correlation strength across different material families is therefore important. Here, we present a combined X-ray absorption spectroscopy (XAS) and resonant inelastic X-ray scattering (RIXS) study of infinite-layer PrNiO$_2$ and SrCuO$_2$ that enables fair comparison of their interaction strengths. For both compounds, we study the orbital and magnetic excitations and extract their dispersions along high-symmetry directions. Using a single-band Hubbard model and including higher-order exchange interactions, we derive the correlation factor $U/t$ for both compounds. A key finding is that despite a smaller Coulomb repulsion $U$, PrNiO$_2$ exhibits a correlation strength that is 20% stronger than that of its isostructural cuprate counterpart SrCuO$_2$. This indicates that a moderation of the correlation strength may further optimize superconductivity in nickelates.

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Xunyang Hong, Yuetong Wu, Ying Chan, Sze Tung Li, I. Biało, L. Martinelli, A. Drewanowski, Qiang Gao, Xiaolin Ren, Xingjiang Zhou, Zhihai Zhu, A. Galdi, D. G. Schlom, K. M. Shen, J. Choi, M. Garcia Fernandez, Ke-Jin Zhou, N. B. Brookes, H. M. Rønnow, Qisi Wang, J. Chang. 2025-11-12. Impact of Electron Correlations on Infinite-Layer Cuprates and Nickelates. https://doi.org/10.1038/s43246-026-01175-0

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