Doping evolution of spin excitations in La$_{3-x}$Sr$_{x}$Ni$_2$O$_7$/SrLaAlO$_4$ superconducting thin films

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Main Authors: Zhong, Hengyang, Hao, Bo, Chen, Anni, Huang, Xinru, Li, Chunyi, Zhang, Wenting, Liu, Chang, Kummer, Kurt, Brookes, Nicholas, Nie, Yuefeng, Schmitt, Thorsten, Lu, Xingye
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Published: 2026
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author Zhong, Hengyang
Hao, Bo
Chen, Anni
Huang, Xinru
Li, Chunyi
Zhang, Wenting
Liu, Chang
Kummer, Kurt
Brookes, Nicholas
Nie, Yuefeng
Schmitt, Thorsten
Lu, Xingye
author_facet Zhong, Hengyang
Hao, Bo
Chen, Anni
Huang, Xinru
Li, Chunyi
Zhang, Wenting
Liu, Chang
Kummer, Kurt
Brookes, Nicholas
Nie, Yuefeng
Schmitt, Thorsten
Lu, Xingye
contents Ambient-pressure superconductivity in compressively strained bilayer nickelate films enables direct spectroscopic tests of pairing scenarios, yet how magnetism evolves with carrier doping remains largely unexplored. Here we use Ni $L_3$-edge resonant inelastic x-ray scattering (RIXS) to track electronic and spin excitations in coherently strained La$_{3-x}$Sr$_x$Ni$_2$O$_7$/SrLaAlO$_4$ thin films ($x=0$, $0.09$, $0.21$ and $0.38$), spanning superconducting and overdoped non-superconducting regimes at essentially fixed epitaxial strain. Transport confirms superconductivity for $x\le0.21$ and a weakly insulating normal state at $x=0.38$. The $dd$-excitation manifold evolves weakly up to $x=0.21$, whereas the $\sim0.4$ eV and $\sim1.6$ eV features broaden and lose intensity at $x=0.38$. In the superconducting films, dispersive spin excitations persist along both $[H, H]$ and $[H, 0]$ with nearly doping-independent undamped dispersions and only a modest reduction of spectral weight, consistent with robust double-stripe correlations. By contrast, at $x=0.38$ the magnetic response becomes strongly broadened and weakened, with enhanced damping and $\sim50\%$ lower spectral weight, indicating a collapse of coherent double-stripe spin excitations. The concomitant suppression of magnetic coherence and superconductivity establishes a direct doping-controlled link between magnetism and superconductivity in bilayer nickelate films.
format Preprint
id arxiv_https___arxiv_org_abs_2603_01120
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Doping evolution of spin excitations in La$_{3-x}$Sr$_{x}$Ni$_2$O$_7$/SrLaAlO$_4$ superconducting thin films
Zhong, Hengyang
Hao, Bo
Chen, Anni
Huang, Xinru
Li, Chunyi
Zhang, Wenting
Liu, Chang
Kummer, Kurt
Brookes, Nicholas
Nie, Yuefeng
Schmitt, Thorsten
Lu, Xingye
Superconductivity
Strongly Correlated Electrons
Ambient-pressure superconductivity in compressively strained bilayer nickelate films enables direct spectroscopic tests of pairing scenarios, yet how magnetism evolves with carrier doping remains largely unexplored. Here we use Ni $L_3$-edge resonant inelastic x-ray scattering (RIXS) to track electronic and spin excitations in coherently strained La$_{3-x}$Sr$_x$Ni$_2$O$_7$/SrLaAlO$_4$ thin films ($x=0$, $0.09$, $0.21$ and $0.38$), spanning superconducting and overdoped non-superconducting regimes at essentially fixed epitaxial strain. Transport confirms superconductivity for $x\le0.21$ and a weakly insulating normal state at $x=0.38$. The $dd$-excitation manifold evolves weakly up to $x=0.21$, whereas the $\sim0.4$ eV and $\sim1.6$ eV features broaden and lose intensity at $x=0.38$. In the superconducting films, dispersive spin excitations persist along both $[H, H]$ and $[H, 0]$ with nearly doping-independent undamped dispersions and only a modest reduction of spectral weight, consistent with robust double-stripe correlations. By contrast, at $x=0.38$ the magnetic response becomes strongly broadened and weakened, with enhanced damping and $\sim50\%$ lower spectral weight, indicating a collapse of coherent double-stripe spin excitations. The concomitant suppression of magnetic coherence and superconductivity establishes a direct doping-controlled link between magnetism and superconductivity in bilayer nickelate films.
title Doping evolution of spin excitations in La$_{3-x}$Sr$_{x}$Ni$_2$O$_7$/SrLaAlO$_4$ superconducting thin films
topic Superconductivity
Strongly Correlated Electrons
url https://arxiv.org/abs/2603.01120