Splitting of guest atom sites and lattice thermal conductivity of type-I and type-III clathrate compounds in the Ba-Ga-Ge system
Splitting of guest atom sites and lattice thermal conductivity of type-I and type-III clathrate compounds in the Ba-Ga-Ge system
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DOI：
10.1016/j.actamat.2006.08.020
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发表时间：
2006-12-01
期刊：
影响因子：
9.4
通讯作者：
Inui, Haruyuki
中科院分区：
文献类型：
--
作者：
Okamoto, Norihiko L.;Kim, Jung-Hwan;Inui, Haruyuki
用同步X射线粉末衍射法在室温下研究了Ba-Ga-Ge系中I类和III类笼状化合物的晶体结构，并用单位和裂位模型描述了被认为在笼子中“作响”的Ba原子的热振动。从两种化合物中Ba原子的热振动幅度和包络笼形状随Ga含量的变化来看，裂位模型更符合实际。当用裂位模型描述时，两种化合物的室温晶格导热系数值都随着Ba位分裂距离的增加而减小，表明分裂距离可以作为描述笼子中Ba客体原子的热振动(叮当运动)程度的一个参数。(C)2006 Acta Materialia Inc.由爱思唯尔有限公司出版。保留所有权利。
The crystal structures of type-I and type-III clathrate compounds in the Ba-Ga-Ge system have been investigated by synchrotron X-ray powder diffraction at room temperature with single- and split-site models to describe thermal vibration of the Ba atoms that are believed to 'rattle' in the encapsulating cages. The split-site model is verified to be more plausible when judged from the changes of the extent of thermal vibration of the Ba atoms and the shape changes of the encapsulating cages with the Ga content for both types of compound. When described with the split-site model, the value of lattice thermal conductivity at room temperature decreases with increasing split distance of the Ba atom site for both types of compound, indicating that the split distance can be used as a parameter to describe the extent of thermal vibration (rattling motion) of the Ba guest atoms in the encapsulating cages. (c) 2006 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.