KFe2Se2 is the Parent Compound of K-Doped Iron Selenide Superconductors
KFe2Se2 is the Parent Compound of K-Doped Iron Selenide Superconductors
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DOI：
10.1103/physrevlett.109.057003
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发表时间：
2012-07-31
影响因子：
8.6
通讯作者：
Xue, Qi-Kun
中科院分区：
文献类型：
--
作者：
Li, Wei;Ding, Hao;Xue, Qi-Kun
我们阐明了新发现的K掺杂硒化铁（KxFe 2-ySe 2-z）超导体中存在的争议。利用扫描隧道显微镜和光谱学研究了KxFe_（2-y）Se_（2-z）超导体的母体化合物KFe_（2-y）Se_（2-z）。KFe_2Se_2中的超导电性是由Se空位或与反铁磁化合物K_2Fe_4Se_5相互作用引起的。在KxFe_（2-y）Se_（2-z）中，共存在四种相：母体化合物KFe_（2-y）Se_（2-z）、具有根2 ×根5电荷有序的超导KFe_（2-y）Se_（2-z）、具有Se空位的超导KFe_（2-z）和具有根5 ×根5 Fe空位有序的绝缘KFe_（4-y）Se_（5-y）。在标准分子束外延条件下，相分离发生在介观尺度。
We elucidate the existing controversies in the newly discovered K-doped iron selenide ( KxFe2-ySe2-z) superconductors. The stoichiometric KFe2Se2 with root 2 x root 2 p charge ordering was identified as the parent compound of KxFe2-ySe2-z superconductor using scanning tunneling microscopy and spectroscopy. The superconductivity is induced in KFe2Se2 by either Se vacancies or interacting with the antiferromagnetic K2Fe4Se5 compound. In total, four phases were found to exist in KxFe2-ySe2-z: parent compound KFe2Se2, superconducting KFe2Se2 with root 2 x root 5 charge ordering, superconducting KFe2Se2-z with Se vacancies, and insulating K2Fe4Se5 with root 5 x root 5 Fe vacancy order. The phase separation takes place at the mesoscopic scale under standard molecular beam epitaxy conditions.