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arXiv · 2508.11581

Stabilizing and Tuning Superconductivity in La$_3$Ni$_2$O$_{7-\delta}$ Films: Oxygen Recycling Protocol Reveals Hole-Doping Analogue

Lifen Xiang·Siyi Lei·Xiaolin Ren·Ziao Han·Zijian Xu·X. J. Zhou·Zhihai Zhu
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Abstract

The recent achievement of superconductivity in La$_3$Ni$_2$O$_{7-\delta}$ with transition temperatures exceeding 40 K in thin films under compressive strain and 80 K in bulk crystals under high pressure opens new avenues for research on high-temperature superconductivity. The realization of superconductivity in thin films requires delicate control of growth conditions, which presents significant challenges in the synthesis process. Furthermore, the stability of superconducting La$_3$Ni$_2$O$_{7-\delta}$ films is compromised by oxygen loss, which complicates their characterization. We introduce an effective recycling protocol that involves oxygen removal in a precursor phase followed by ozone-assisted annealing, which restores superconducting properties. By tuning the oxygen content, we construct an electronic phase diagram that highlights oxygen addition as a potential analogue to hole doping via La substitution with Sr, providing insights into the doping mechanism and guiding future material optimization.

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Lifen Xiang, Siyi Lei, Xiaolin Ren, Ziao Han, Zijian Xu, X. J. Zhou, Zhihai Zhu. 2025-08-15. Stabilizing and Tuning Superconductivity in La$_3$Ni$_2$O$_{7-\delta}$ Films: Oxygen Recycling Protocol Reveals Hole-Doping Analogue. https://doi.org/10.1103/h9ls-y4s7

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