A comparative theoretical study of the Peierls distortion in type-II alkaline-doped clathrates
A comparative theoretical study of the Peierls distortion in type-II alkaline-doped clathrates
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II型碱掺杂包合物中Peierls畸变的比较理论研究
DOI：
10.1209/epl/i2003-00623-5
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发表时间：
2003
期刊：
影响因子：
1.8
通讯作者：
P. Mélinon
中科院分区：
文献类型：
--
作者：
H. Libotte;J. Gaspard;A. Miguel;P. Mélinon
我们证明了在膨胀金属中可能发生佩尔斯变形。当钠膨胀时，它会发生对称性破坏，形成双原子分子。这种现象是电子不稳定机制的结果。正如最近的EXAFS实验所显示的那样，水合物笼中的钠原子不会停留在笼的中心。我们用两种截然不同的方法来描述这种畸变：基于密度泛函理论的局部密度近似的从头计算研究和紧密结合描述。本研究也扩展到其他碱掺杂硅包合物。这种二聚过程与氢二聚体的存在有关。
We show that a Peierls distortion may occur in expanded metals. When the sodium is expanded it undergoes a symmetry breaking and diatomic molecules are formed. This phenomenon is a result of an electronic instability mechanism. As shown by recent EXAFS experiments, sodium atoms included in chlathrate cages do not stay at the center of the cages. We describe this distortion by two very different methods: an ab initio study based on the local density approximation of the density-functional theory and a tight-binding description. This study is also extended to the other alkaline-doped silicon clathrates. This dimerization process is related to hydrogen dimer existence.