Cation vacancy order in the K0.8+xFe1.6-ySe2 system: Five-fold cell expansion accommodates 20% tetrahedral vacancies
Cation vacancy order in the K0.8+xFe1.6-ySe2 system: Five-fold cell expansion accommodates 20% tetrahedral vacancies
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DOI：
10.1039/c1sc00070e
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发表时间：
2011-01-01
期刊：
影响因子：
8.4
通讯作者：
Claridge, J. B.
中科院分区：
文献类型：
--
作者：
Bacsa, J.;Ganin, A. Y.;Claridge, J. B.
在K0.93(1)Fe1.52(1)Se2和K0.862(3)Fe1.563(4)Se2这两种精细成分的晶体中，四面体空位的排序使母体ThCr2Si2单元胞在ab平面上扩展了5倍，可以在方形FeSe层内的单个位点上容纳20%的空位。通过碱金属和铁空位水平的耦合，铁电荷态保持在+2附近，产生了一种可以在平均和局部结构水平上运行的潜在掺杂机制。
Ordering of the tetrahedral site vacancies in two crystals of refined compositions K0.93(1)Fe1.52(1)Se2 and K0.862(3)Fe1.563(4)Se2 produces a fivefold expansion of the parent ThCr2Si2 unit cell in the ab plane which can accommodate 20% vacancies on a single site within the square FeSe layer. The iron charge state is maintained close to +2 by coupling of the level of alkali metal and iron vacancies, producing a potential doping mechanism which can operate at both average and local structure levels.