四方相 β-Fe1-xSe 中的 Fe 空位有序和超导电性。
Fe-vacancy order and superconductivity in tetragonal β-Fe1-xSe.
机构信息
Institute of Physics, Academia Sinica, Taipei 115, Taiwan.
出版信息
Proc Natl Acad Sci U S A. 2014 Jan 7;111(1):63-8. doi: 10.1073/pnas.1321160111. Epub 2013 Dec 18.
Several superconducting transition temperatures in the range of 30-46 K were reported in the recently discovered intercalated FeSe system (A1-xFe2-ySe2, A = K, Rb, Cs, Tl). Although the superconducting phases were not yet conclusively decided, more than one magnetic phase with particular orders of iron vacancy and/or potassium vacancy were identified, and some were argued to be the parent phase. Here we show the discovery of the presence and ordering of iron vacancy in nonintercalated FeSe (PbO-type tetragonal β-Fe1-xSe). Three types of iron-vacancy order were found through analytical electron microscopy, and one was identified to be nonsuperconducting and magnetic at low temperature. This discovery suggests that the rich-phases found in A1-xFe2-ySe2 are not exclusive in Fe-Se and related superconductors. In addition, the magnetic β-Fe1-xSe phases with particular iron-vacancy orders are more likely to be the parent phase of the FeSe superconducting system instead of the previously assigned β-Fe1+δTe.
在最近发现的插层 FeSe 体系（A1-xFe2-ySe2，A = K、Rb、Cs、Tl）中，报道了几个超导转变温度在 30-46 K 范围内的超导相。尽管超导相尚未得到明确的确定，但已经确定了具有特定铁空位和/或钾空位序的多个磁相，并且一些被认为是母相。在这里，我们发现了非插层 FeSe（PbO 型四方β-Fe1-xSe）中存在铁空位和有序。通过分析电子显微镜发现了三种类型的铁空位有序，其中一种被确定为在低温下不超导和磁性。这一发现表明，在 A1-xFe2-ySe2 中发现的丰富相在 Fe-Se 和相关超导体中并非独一无二。此外，具有特定铁空位序的磁性β-Fe1-xSe 相更有可能是 FeSe 超导体系的母相，而不是之前指定的β-Fe1+δTe。
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