Strong Coupling of the Fe-Spin State and the As-As Hybridization in Iron-Pnictide Superconductors from First-Principle Calculations

被引：250

作者：

Yildirim, T. ^{[1
,2
]}

机构：

[1] NIST, Ctr Neutron Res, Gaithersburg, MD 20899 USA

[2] Univ Penn, Dept Mat Sci & Engn, Philadelphia, PA 19104 USA

来源：

PHYSICAL REVIEW LETTERS | 2009年 / 102卷 / 03期

关键词：

D O I：

10.1103/PhysRevLett.102.037003

中图分类号：

O4 [物理学];

学科分类号：

0702 ;

摘要：

From first-principles calculations, we unravel surprisingly strong interactions between arsenic ions in iron pnictides, the strength of which is controlled by the Fe-spin state. Reducing the Fe-magnetic moment weakens the Fe-As bonding, and in turn, increases As-As interactions, causing giant reduction in the c axis. For the CaFe2As2 system, this reduction is as large as 1.4 A. Since the large c reduction has been recently observed only under high pressure, our results suggest that the iron magnetic moment should be present in Fe-pnictides at all times at ambient pressure. Finally, the conventional electron-phonon coupling in the collapsed phase of CaFe2As2 gives a maximum T-c of 0.6 K and cannot explain the similar to 12 K superconductivity observed in some experiments. Implications of these findings on the mechanism of superconductivity in iron pnictides are discussed.

引用

页数：4

共 23 条

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