Tetrahedral Complexity in Amorphous Networks: A Possible Clue for the Unique Properties of Phase‐Change Materials,Physica Status Solidi-Rapid Research Letters

当前位置： X-MOL 学术 › Phys. Status Solidi. Rapid Res. Lett. › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

Tetrahedral Complexity in Amorphous Networks: A Possible Clue for the Unique Properties of Phase‐Change Materials
Physica Status Solidi-Rapid Research Letters ( IF 2.5 ) Pub Date : 2020-11-18 , DOI: 10.1002/pssr.202000490
Matthieu Micoulaut ₁ , Hugo Flores-Ruiz ₂ , Annie Pradel ₃ , Andrea Piarristeguy ₃

Affiliation

A typical binary amorphous telluride GeTe₂ is investigated from first‐principles molecular dynamics simulations. After a comparison with chemical analogs from neutron or X‐ray diffraction experiments, such as GeO₂ or GeSe₂, the structure of this material is studied by examining real and reciprocal space properties. It is found that the base geometrical motifs of the germanium atom can be either in tetrahedral or in defected coordinations involving pyramidal units. A review of previous results for other compositions reveals that such binary Ge tellurides contain soft tetrahedra, at variance with lighter chalcogenides, such as GeS and GeSe, and are characterized by an increased angular bending motion (typically 20°) as compared with, e.g., GeS (5°). In addition, for amorphous Ge‐rich materials, GeTe₂ and GeTe, a secondary tetrahedral geometry appears, related to the presence of GeGe bonds, having a larger mean angle of about 125°. These typical features not only relate to characteristics observed from scattering experiments but may also be a crucial feature for the understanding of the phase‐change phenomena.

中文翻译：

非晶网络中的四面体复杂性：相变材料独特性质的可能线索

通过第一性原理的分子动力学模拟研究了典型的二元非晶态碲化物GeTe ₂。在与来自中子或X射线衍射实验的化学类似物（例如GeO ₂或GeSe _{2）进行比较之后}，通过检查真实的和倒数的空间性质来研究这种材料的结构。发现锗原子的基本几何图案可以是四面体的，也可以是锥体结构的缺陷配位。对于其它组合物以前的结果的回顾表明，这样的二元锗碲化物含有软四面体，在方差与打火机硫属化物，例如Ge  S和葛Se和Se的特征在于，与例如GeS（5°）相比，角弯曲运动增加（通常为20 °）。另外，对于非晶态的富含Ge的材料GeTe ₂和GeTe，出现了第二个四面体几何形状，与GeGe键的存在有关，其平均角较大，约为125°。这些典型特征不仅与从散射实验中观察到的特征有关，而且对于理解相变现象也可能是至关重要的特征。

更新日期：2020-11-18

点击分享查看原文

点击收藏

阅读更多本刊最新论文本刊介绍/投稿指南11