Anomalous correlation effects and unique phase diagram of electron-doped FeSe revealed by photoemission spectroscopy

作者：Chenhaoping Wen, Haichao Xu, C. Chen, Zhichun Huang, Xin Lou, Yan Pu, Qianqian Song, B. P. Xie, Mahmoud Abdel-Hafiez, Д. А. Чареев, A. N. Vasiliev, Rui Peng, Donglai Feng · 发表于：Nature Communications · 年份：2016 · DOI：10.1038/ncomms10840 · 被引用次数：177 · 研究领域：Iron-based superconductors research、Physics of Superconductivity and Magnetism、Advanced Condensed Matter Physics

FeSe layer-based superconductors exhibit exotic and distinctive properties. The undoped FeSe shows nematicity and superconductivity, while the heavily electron-doped KxFe2-ySe2 and single-layer FeSe/SrTiO3 possess high superconducting transition temperatures that pose theoretical challenges. However, a comprehensive study on the doping dependence of an FeSe layer-based superconductor is still lacking due to the lack of a clean means of doping control. Through angle-resolved photoemission spectroscopy studies on K-dosed thick FeSe films and FeSe0.93S0.07 bulk crystals, here we reveal the internal connections between these two types of FeSe-based superconductors, and obtain superconductivity below ∼ 46 K in an FeSe layer under electron doping without interfacial effects. Moreover, we discover an exotic phase diagram of FeSe with electron doping, including a nematic phase, a superconducting dome, a correlation-driven insulating phase and a metallic phase. Such an anomalous phase diagram unveils the remarkable complexity, and highlights the importance of correlations in FeSe layer-based superconductors.