Persistent paramagnons in high-temperature infinite-layer nickelate superconductors
Abstract
The recent discovery of high-temperature superconductivity in hole-doped SmNiO, exhibiting the record-high transition temperature among infinite-layer (IL) nickelates, has opened a new avenue for exploring design principles of superconductivity. Experimentally determining the electronic structure and magnetic interactions in this new system is crucial to elucidating the mechanism behind the enhanced superconductivity. Here, we report a Ni -edge resonant inelastic x-ray scattering (RIXS) study of superconducting Sm-based IL nickelate thin films SmEuCaSrNiO (SECS). Dispersive paramagnonic excitations are observed in both optimally and overdoped SECS samples, supporting a spin-fluctuation-mediated pairing scenario. However, despite the two-fold enhancement of in the Sm-based nickelates compared to their Pr-based counterparts, the effective exchange coupling strength is reduced by approximately . This behavior contrasts with hole-doped cuprates, where magnetic interactions correlate positively with , highlighting essential differences in their superconducting mechanisms.
Cite
@article{arxiv.2507.18373,
title = {Persistent paramagnons in high-temperature infinite-layer nickelate superconductors},
author = {Yujie Yan and Ying Chan and Xunyang Hong and S. Lin Er Chow and Zhaoyang Luo and Yuehong Li and Tianren Wang and Yuetong Wu and Izabela Biało and Nurul Fitriyah and Saurav Prakash and Xing Gao and King Yau Yip and Qiang Gao and Xiaolin Ren and Jaewon Choi and Ganesha Channagowdra and Jun Okamoto and Xingjiang Zhou and Zhihai Zhu and Liang Si and Mirian Garcia-Fernandez and Ke-Jin Zhou and Hsiao-Yu Huang and Di-Jing Huang and Johan Chang and A. Ariando and Qisi Wang},
journal= {arXiv preprint arXiv:2507.18373},
year = {2025}
}
Comments
Supplementary Information available upon request