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arXiv 1111.2597cond-mat.supr-con
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KxFe2-ySe2的局域结构无序与超导电性

Local structural disorder and superconductivity in KxFe2-ySe2

Hyejin Ryu, Hechang Lei, A. I. Frenkel, C. Petrovic

摘要:

本文报道了在K_(0.69)(2)Fe_(1.45)(1)Se_(2.00)(1))单晶中,通过退火和淬火工艺获得了明显增强的磁矩和体超导性。在K0.69(2)Fe1.45(1)Se2.00(1)晶胞中存在两个Fe位:Fe 1,具有较高的对称性和较长的平均Fe-Se键长; Fe 2,具有较低的对称性和较短的平均Fe-Se键长。用变温X射线吸收精细结构(XAFS)分析了K0.69(2)Fe 1.45(1)Se 2.00(1)晶体的结构,结果表明:K0.69(2)Fe 1.45(1)Se 2.00(1)晶体的平均Fe-Se键长增加,静态无序度降低。我们的研究结果表明,非零人口的Fe 1网站是关键的结构参数,支配体超导电性。我们还显示了明确的证据表明,Fe 1网站进行更高的磁矩比Fe 2网站。

英文摘要:

We report significantly enhanced magnetic moment in K0.69(2)Fe1.45(1)Se2.00(1) single crystals with sharp Tc and bulk superconductivity obtained by postannealing and quenching process. There are two Fe sites in the K0.69(2)Fe1.45(1)Se2.00(1) unit cell: Fe1, which has higher symmetry with longer average Fe-Se bond length, and Fe2, which has lower symmetry with shorter average Fe-Se bond length. Temperature-dependent x-ray absorption fine-structure (XAFS) analysis results on quenched and as-grown K0.69(2)Fe1.45(1)Se2.00(1) crystals show that quenched K0.69(2)Fe1.45(1)Se2.00(1) have increased average Fe-Se bond length and decreased static disorder. Our results indicate that nonzero population of Fe1 sites is the key structural parameter that governs the bulk superconductivity. We also show clear evidence that Fe1 sites carry higher magnetic moment than Fe2 sites.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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