Local structure response of phase separation and iron-vacancy order in Kx Fe2-y Se2 superconductor

A. Iadecola*, B. Joseph, M. Bendele, G. Aquilanti, H. Takeya, Y. Mizuguchi, Y. Takano, T. Mizokawa, N. L. Saini

*この研究の対応する著者

研究成果: Article査読

7 被引用数 (Scopus)

抄録

We have studied the local structure of a KxFe2-ySe2 superconductor across the phase separation and iron-vacancy order-disorder temperatures (respectively at ∼520 K and ∼580 K). The combination of Fe K edge and Se K edge extended x-ray absorption fine-structure (EXAFS) measurements reveal the glassy local structure of KxFe2-ySe2, with anomalous behavior of local atomic displacements. We find that the Fe-Se distance remains temperature independent while the Fe-Fe distance suffers a substantial effect of the phase separation. Furthermore, the Fe-Se network shows a reduced disorder in the phase separation regime at lower temperature. The x-ray absorption near-edge structure features follow the local structure anomaly observed by EXAFS and reveal substantially reduced Fe 3d-Se 4p hybridization in the iron-vacancy disordered phase at higher temperature. The results provide further information on the role of nanoscale atomic displacements in the peculiar coexistence of different electronic phases in KxFe2-ySe2 with a filamentary superconducting state embedded in the iron-vacancy ordered magnetic texture.

本文言語English
論文番号174509
ジャーナルPhysical Review B - Condensed Matter and Materials Physics
90
17
DOI
出版ステータスPublished - 2014 11 20
外部発表はい

ASJC Scopus subject areas

  • 電子材料、光学材料、および磁性材料
  • 凝縮系物理学

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