Hu Yi, Liang Keyi, Li Jie, Li Zhijie, Meng Fanyu, Lei Hechang, Wang Jiyuan, Wen Huizhen, Zhang Ruozhou, Cai Jiaqiang, Zhang Jinglei, Lu Yi, Wang Yihua, Xue Qi-Kun, Zhang Ding
State Key Laboratory of Low Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing, China.
State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai, China.
Nat Commun. 2025 Aug 7;16(1):7305. doi: 10.1038/s41467-025-62624-x.
Merging superconductivity and ferromagnetism in a single material may promise unparalleled quantum properties for next-generation devices. Here, we bring together the two antagonistic phenomena at a record-high temperature via electric-field controlled lithiation of FeSe. The in-situ gating allows us to switch the simple compound of FeSe between a nonmagnetic superconductor and a superconducting ferromagnet. In the latter state, itinerant ferromagnetism persists from above 200 K to a temperature well below the superconducting transition temperature (45 K), as demonstrated not only by magneto-transport but also via scanning superconducting quantum interference device (sSQUID) microscopy. Interestingly, applying certain in-plane magnetic fields enhances superconductivity, reflecting the intimate interplay between high-temperature superconductivity and ferromagnetism. Density-functional theory calculations further reveal the instability of FeSe toward ferromagnetism at a moderate lithium concentration. These findings open up fresh opportunities in iron-based superconductors that interface dissipationless electronics and spintronics.
在单一材料中融合超导性和铁磁性有望为下一代器件带来无与伦比的量子特性。在此，我们通过对FeSe进行电场控制的锂化，在创纪录的高温下将这两种相互对立的现象结合在一起。原位栅极使我们能够在非磁性超导体和超导铁磁体之间切换简单的FeSe化合物。在后者状态下，巡游铁磁性从200 K以上持续到远低于超导转变温度（45 K）的温度，这不仅通过磁输运得到证明，还通过扫描超导量子干涉器件（sSQUID）显微镜得到证实。有趣的是，施加某些面内磁场会增强超导性，这反映了高温超导性和铁磁性之间的紧密相互作用。密度泛函理论计算进一步揭示了在适度锂浓度下FeSe对铁磁性的不稳定性。这些发现为连接无耗散电子学和自旋电子学的铁基超导体开辟了新的机遇。
