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arXiv 1104.4941cond-mat.supr-concond-mat.str-el
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K-PDMATHAAB-Fe $_{2-y}$-Se $_2$超导体中的电子和磁性phase diagram

Electronic and magnetic phase diagram in K$_x$Fe$_{2-y}$Se$_2$ superconductors

Y. J. Yan, M. Zhang, A. F. Wang, J. J. Ying, Z. Y. Li, W. Qin, X. G. Luo, J. Q. Li, Jiangping Hu, X. H. Chen

摘要:

反铁磁性与超导电性之间的关联与竞争是所有高温超导体研究中最基本的问题之一。高温铜氧化物超导体中的超导电性源于通过掺杂抑制反铁磁(AFM)莫特绝缘体相1,而铁磷属元素化物高温超导体中的超导电性源于AFM半金属,并且可以与AFM有序2 -9共存。这两种材料在相图中的关键区别引发了许多有趣的争论,即这两种材料是否可以被放在同一个类别中来理解超导性的机制。最近,在铁硫属化物超导体AxFe 2-ySe 2(A=K,Rb和Cs)10-12中报道了32 K下的超导电性,其具有与铁磷属化物AFe 2As 2(A=Ba,Sr,Ca和K)13-15相同的结构。在这里,我们报告的电子和磁性相图的KxFe 2-ySe 2系统作为一个功能的Fe价。我们发现了两个AFM绝缘相,并揭示了超导相夹在它们之间,并给出了直接的证据,在AxFe 2-ySe 2的超导电性起源于AFM绝缘母体化合物。这两个绝缘相的特征在于由Fe空位有序引起的两个不同的超结构,其调制波矢分别为q1=(1/5,3/5,0)和q2=(1/4,3/4,0)。这些实验结果有力地表明,铁基超导体和铜酸盐有着共同的起源和超导机制。

英文摘要:

The correlation and competition between antiferromagnetism and superconductivity are one of the most fundamental issues in all of high temperature superconductors. The superconductivity in high temperature cuprate superconductors arises from suppressing an antiferromagnetic (AFM) Mott insulator phase by doping1 while that in iron-pnictide high temperature superconductors arises from AFM semimetals and can coexist with AFM orders2-9. This key difference marked in their phase diagrams has raised many intriguing debates about whether the two materials can be placed in the same category to understand the mechanism of superconductivity. Recently, superconductivity at 32 K has been reported in iron-chalcogenide superconductors AxFe2-ySe2 (A=K, Rb, and Cs)10-12, which have the same structure as that of iron-pnictide AFe2As2 (A=Ba, Sr, Ca and K)13-15. Here, we report electronic and magnetic phase diagram of KxFe2-ySe2 system as a function of Fe valence. We find two AFM insulating phases and reveal that the superconducting phase is sandwiched between them, and give direct evidence that the superconductivity in AxFe2-ySe2 originates from the AFM insulating parent compounds. The two insulating phases are characterized by two distinct superstructures caused by Fe vacancy orders with modulation wave vectors of q1=(1/5, 3/5, 0) and q2=(1/4, 3/4, 0), respectively. These experimental results strongly indicate that iron-based superconductors and cuprates share a common origin and mechanism of superconductivity.

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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