Evolution of Eu valence and superconductivity in layered Eu0.5La0.5FBiS2-xSex system
Evolution of Eu valence and superconductivity in layered Eu0.5La0.5FBiS2-xSex system
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层状Eu0.5La0.5FBiS2-xSex体系中Eu价态和超导性的演化
DOI：
10.1103/physrevb.95.064515
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发表时间：
2017
期刊：
影响因子：
--
通讯作者：
N. L. Saini
中科院分区：
文献类型：
--
作者：
Y. Mizuguchi;E. Paris;T. Wakita;G. Jinno;A. Puri;K. Terashima;B. Joseph;O. Miura;T. Yokoya;N. L. Saini
本文用X射线吸收近边结构（XANES）和X射线光电子能谱（XPS）研究了Se取代对层状超导体中Eu价态的影响。Eu边XANES谱表明Eu处于和共存的混合价态。Eu的平均价态从~急剧下降。因此，EuXPS显示Se取代的平均化合价明显降低。BiXPS表明，在（Ch = S，Se）层中的有效电荷载流子略有增加Se取代。在此基础上，讨论了Se取代引起的金属特性可能是由于减少了影响载流子迁移率的面内无序而导致的面内轨道重叠增加。
We have studied the effect of Se substitution on Eu valence in a layeredsuperconductor using a combined analysis of x-ray absorption near-edge structure (XANES) and x-ray photoelectron spectroscopy (XPS) measurements. Eu-edge XANES spectra reveal that Eu is in the mixed valence state with coexistingand. The average Eu valence decreases sharply fromfortofor. Consistently, EuXPS shows a clear decrease in the average valence by Se substitution. BiXPS indicates that effective charge carriers in the(Ch = S, Se) layers are slightly increased by Se substitution. On the basis of the present results it has been discussed that the metallic character induced by Se substitution inis likely to be due to increased in-plane orbital overlap driven by reduced in-plane disorder that affects the carrier mobility.