Details

Autor(en) / Beteiligte

• Dong, Xiaoli
• Zhou, Huaxue
• Yang, Huaixin
• Yuan, Jie
• Jin, Kui
• Zhou, Fang
• Yuan, Dongna
• Wei, Linlin
• Li, Jianqi
• Wang, Xinqiang
• Zhang, Guangming
• Zhao, Zhongxian

Titel

Phase Diagram of (Li1–x Fe x )OHFeSe: A Bridge between Iron Selenide and Arsenide Superconductors

Ist Teil von

• Journal of the American Chemical Society, 2015-01, Vol.137 (1), p.66-69

Ort / Verlag

American Chemical Society

Erscheinungsjahr

2015

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Previous experimental results have shown important differences between iron selenide and arsenide superconductors which seem to suggest that the high-temperature superconductivity in these two subgroups of iron-based families may arise from different electronic ground states. Here we report the complete phase diagram of a newly synthesized superconducting (SC) system, (Li1–x Fe x )­OHFeSe, with a structure similar to that of FeAs-based superconductors. In the non-SC samples, an antiferromagnetic (AFM) spin-density-wave (SDW) transition occurs at ∼127 K. This is the first example to demonstrate such an SDW phase in an FeSe-based superconductor system. Transmission electron microscopy shows that a well-known √5×√5 iron vacancy ordered state, resulting in an AFM order at ∼500 K in A y Fe2–x Se2 (A = metal ions) superconductor systems, is absent in both non-SC and SC samples, but a unique superstructure with a modulation wave vector q = 1/2(1,1,0), identical to that seen in the SC phase of K y Fe2–x Se2, is dominant in the optimal SC sample (with an SC transition temperature T c = 40 K). Hence, we conclude that the high-T c superconductivity in (Li1–x Fe x )­OHFeSe stems from the similarly weak AFM fluctuations as FeAs-based superconductors, suggesting a universal physical picture for both iron selenide and arsenide superconductors.