Discrete Superconducting Phases in FeSe-Derived Superconductors.
/ Authors
T. Ying, Min Wang, Xianxin Wu, Ziyi Zhao, Zhizhen Zhang, B. Song, Ying Li, B. Lei, Qiang Li, Yijun Yu
and 7 more authors
Erjian Cheng, Z. An, Yuanbo Zhang, Xiao-Yu Jia, Wanli Yang, Xianhui Chen, Shiyan Li
/ Abstract
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.
Journal: Physical review letters