Discrete Superconducting Phases in FeSe-Derived Superconductors

作者：Tianping Ying, M. X. Wang, Xianxin Wu, Z. Y. Zhao, Zhizhen Zhang, Boqin Song, Y. C. Li, Bin Lei, Q. Li, Yijun Yu, Erjian Cheng, Zhenghua An, Y. Zhang, Xiaoyu Jia, Wenge Yang, X. H. Chen, S. Y. Li · 发表于：Physical Review Letters · 年份：2018 · DOI：10.1103/physrevlett.121.207003 · 被引用次数：68 · 研究领域：Iron-based superconductors research、Corporate Taxation and Avoidance、Rare-earth and actinide compounds

A general feature of unconventional superconductors is the existence of a superconducting dome in the phase diagram. Here we report a series of discrete superconducting phases in the simplest iron-based superconductor, FeSe thin flakes, by continuously tuning the carrier concentration through the intercalation of Li and Na ions with a solid ionic gating technique. Such discrete superconducting phases are robust against the substitution of 20% S for Se, but they are vulnerable to the substitution of 2% Cu for Fe, highlighting the importance of the iron site being intact. The superconducting phase diagram for FeSe derivatives is given, which is distinct from that of other unconventional superconductors.