Electronic and magnetic phase diagram of β-Fe1.01Se with superconductivity at 36.7 K under pressure
Electronic and magnetic phase diagram of β-Fe1.01Se with superconductivity at 36.7 K under pressure
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DOI：
10.1038/nmat2491
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发表时间：
2009-08-01
期刊：
影响因子：
41.2
通讯作者：
Felser, C.
中科院分区：
文献类型：
--
作者：
Medvedev, S.;McQueen, T. M.;Felser, C.
基于FeAs的新型高温超导体（1）的发现引发了高T-C超导性的新“淘金热”。所有新的超导体都具有相同的FeAs层结构，并且T-C值高达55 K（参考文献2）。最近，已经报道了FeSe的超导电性（参考文献3），它具有相同的铁磷属元素化物层结构，但没有分离层。在这里，我们报告的磁性和电子相图β-Fe-1.Se-01作为温度和压力的函数。在8.9GPa的压力下，超导转变温度从8.5 K上升到36.7 K。然后在更高的压力下下降。由于Fe 2Se 2层之间的分离崩溃，在TC上升的同时观察到体积的显著变化。在整个p-T相图中没有观察到静态磁有序。我们还报告说，在较高的压力（约7 GPa开始，并在38 GPa完成），Fe1.01Se转变为六方的NiAs型结构，并表现出非磁性行为。
The discovery of new high-temperature superconductors(1) based on FeAs has led to a new 'gold rush' in high-T-C superconductivity. All of the new superconductors share the same common structural motif of FeAs layers and reach T-C values up to 55 K (ref. 2). Recently, superconductivity has been reported in FeSe (ref. 3), which has the same iron pnictide layer structure, but without separating layers. Here, we report the magnetic and electronic phase diagram of beta-Fe-1.Se-01 as a function of temperature and pressure. The superconducting transition temperature increases from 8.5 to 36.7 K under an applied pressure of 8.9 GPa. It then decreases at higher pressures. A marked change in volume is observed at the same time as TC rises, owing to a collapse of the separation between the Fe2Se2 layers. No static magnetic ordering is observed for the whole p-T phase diagram. We also report that at higher pressures (starting around 7 GPa and completed at 38 GPa), Fe1.01Se transforms to a hexagonal NiAs-type structure and exhibits non-magnetic behaviour.