Song Yuanhe, Chen Zheng, Zhang Qinghua, Xu Haichao, Lou Xia, Chen Xiaoyang, Xu Xiaofeng, Zhu Xuetao, Tao Ran, Yu Tianlun, Ru Hao, Wang Yihua, Zhang Tong, Guo Jiandong, Gu Lin, Xie Yanwu, Peng Rui, Feng Donglai
Laboratory of Advanced Materials, State Key Laboratory of Surface Physics, and Department of Physics, Fudan University, 200438, Shanghai, China.
Department of Physics, Zhejiang University, 310027, Hangzhou, China.
Nat Commun. 2021 Oct 11;12(1):5926. doi: 10.1038/s41467-021-26201-2.
Enormous enhancement of superconducting pairing temperature (T) to 65 K in FeSe/SrTiO has made it a spotlight. Despite the effort of interfacial engineering, FeSe interfaced with TiO remains the unique case in hosting high T, hindering a decisive understanding on the general mechanism and ways to further improving T. Here we constructed a new high-T interface, single-layer FeSe interfaced with FeO-terminated LaFeO. Large superconducting gap and diamagnetic response evidence that the superconducting pairing can emerge near 80 K, highest amongst all-known interfacial superconductors. Combining various techniques, we reveal interfacial charge transfer and strong interfacial electron-phonon coupling (EPC) in FeSe/LaFeO, showing that the cooperative pairing mechanism works beyond FeSe-TiO. Intriguingly, the stronger interfacial EPC than that in FeSe/SrTiO is likely induced by the stronger interfacial bonding in FeSe/LaFeO, and can explain the higher T according to recent theoretical calculations, pointing out a workable route in designing new interfaces to achieve higher T.
铁硒/钛酸锶中超导配对温度（Tc）大幅提高至65 K，使其备受关注。尽管进行了界面工程方面的努力，但与二氧化钛界面的铁硒仍是具有高Tc的独特案例，这阻碍了对一般机制以及进一步提高Tc方法的决定性理解。在此，我们构建了一种新的高Tc界面，即单层铁硒与以FeO为端的镧铁氧体界面。大的超导能隙和抗磁响应证明超导配对可在近80 K出现，这在所有已知的界面超导体中是最高的。结合多种技术，我们揭示了铁硒/镧铁氧体中的界面电荷转移和强界面电子 - 声子耦合（EPC），表明协同配对机制在铁硒 - 二氧化钛之外也起作用。有趣的是，铁硒/镧铁氧体中比铁硒/钛酸锶更强的界面EPC可能是由铁硒/镧铁氧体中更强的界面键合诱导的，并且根据最近的理论计算可以解释更高的Tc，这指出了设计新界面以实现更高Tc的可行途径。
