Dopant ordering and enhancement of superconducting transition temperature induced by co-doping of iron-based superconductors

铁基超导体由交替排列的二维Fe 2As 2层和间隔层组成。为了实现更高的转变温度Tc，需要寻找新型的隔离层来优化Fe 2As 2层的电子态。迄今为止报道的间隔层由离子化学键组成。在本研究中，我们发现了铁基超导体Ca_（10）（PtnAs_8）（Fe_（2-x）PtxAs_2）_5（n = 3，4），PtnAs_8间隔层由共价化学键组成。在β相（n = 3）中观察到Tc= 17 K，其中Pt和空位在间隔层中是有序的。通过调整Pt和空位的量，α相的Tc提高到38 K（n = 4）。我们的结果表明，各种间隔层可以包括在铁基超导体。

Iron-based superconductors consist of alternating two-dimensional Fe2As2layers and spacer layers. In order to realize higher transition temperature Tc, it is essential to seek novel spacer layers to optimize the electronic state in Fe2As2layer. The spacer layers reported so far consist of ionic chemical bonds. In this study, we discovered iron-based superconductors Ca10(PtnAs8)(Fe2-xPtxAs2)5(n = 3, 4) with PtnAs8spacer layers made of covalent chemical bonds. Tc= 17 K was observed in the beta phase (n = 3), in which Pt and vacancy are ordered in the spacer layer. By adjusting the amounts of Pt and vacancy, Tcwas raised up to 38 K in the alpha phase (n = 4). Our results demonstrated that a variety of spacer layers can be included in the iron-based superconductors.