Disparate atomic displacements in skutterudite-type LaFe3CoSb12, a model for thermoelectric behavior.
Disparate atomic displacements in skutterudite-type LaFe3CoSb12, a model for thermoelectric behavior.
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DOI：
10.1107/s0108768198018345
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发表时间：
1999-06
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影响因子：
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通讯作者：
Chakoumakos;Sales;Mandrus;Keppens
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文献类型：
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作者：
Chakoumakos;Sales;Mandrus;Keppens
十二锑化三铁钴镧中的均方原子位移，用单晶中子衍射测定为温度的函数，表明La原子在室温下表现出非常大的位移，U（eq）= 0.0196（9）<$（2），因为它太小而不能填充由M（4）Sb（12）的角连接八面体框架形成的原子笼，M = Fe，网站占用细化显示25%的La网站和实际的Fe：Co比为2.17：1的空缺。的原子位移的温度依赖性的分析确定了一个显着的温度无关的组分的La原子归因于静态无序，这相当于19%的室温值。La原子的大幅度振动可以有效地与晶格对热导率的贡献的急剧下降联系起来，这是改善这些材料的热电行为的关键因素。这种结构-性能关系为热电材料的开发提供了一个新的范例。
Mean-square atomic displacements in lanthanum triiron cobalt dodecaantimonide, determined as a function of temperature using single-crystal neutron diffraction, show that the La atom exhibits an anomalously large displacement at room temperature, U(eq) = 0.0196 (9) Å(2), because it is too small to fill the atomic cage formed by the corner-linked octahedral framework of M(4)Sb(12), M = Fe, Co. Site-occupancy refinements show 25% vacancies on the La site and an actual Fe:Co ratio of 2.17:1. Analysis of the temperature dependence of the atomic displacements identifies a significant temperature-independent component for the La atom ascribed to static disorder, which amounts to 19% of the room-temperature value. The large-amplitude rattling of the La atom can be effectively linked to the dramatic decrease of the lattice contribution to the thermal conductivity, which is a key factor for improving the thermoelectric behavior of these materials. This structure-property relationship offers a new paradigm for the exploration of thermoelectric materials.