Heterogeneous Structural Distortions Induced by In-Plane and Out-of-Plane Doping in Iron-Based Superconductors
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For iron-based superconductors, both the in-plane and out-of-plane doping can cause the superconductivity. In this contribution, we investigated both the electronic structure and local lattice structure induced by in-plane and out-of-plane doping in SmFeAsO-based superconductors probed by X-ray absorption spectroscopy. Data pointed out that upon out-of-plane doping the charge reservoir layers and superconductive layers become closer, enhancing the electron transfer from SmO to FeAs layers, and in the end, almost all the electron carriers were gathered around Fe atoms. On the other hand, for in-plane doping, we observed the elongation of Sm–As bonds but the shrinkage of FeAs layers that promoted the transfer of electron carriers on superconductive layers. Accordingly, it is because of the heterogeneous structural distortions that lead to the different superconducting mechanism of in-plane and out-of-plane doping in iron-based superconductors.
KeywordsIron-based superconductors XAS In-plane doping Out-of-plane doping
This work was partly supported by the Natural Science Foundation of China (NSFC 11405089), the Natural Science Foundation of Jiangsu Province of China (Nos. BK20130855 and BK20130376), and the Scientific Research Foundation of Nanjing University of Posts and Telecommunications (Nos. NY213053 and NY213181).
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