GeSb2Te4亚稳相原子结构的透射电子显微学研究

GeSb₂Te₄亚稳相原子结构的透射电子显微学研究

朱海音，宋建祥，刘显强^*

（北京工业大学固体微结构与性能研究所，北京 100124）

摘 要：由于Ge原子在相变过程中的重要作用，使其在GeSbTe合金亚稳相中的局域结构长期以来为人们所关注。本文利用电子衍射技术和基于电子衍射的径向分布函数，以及高分辨电子显微学，对GeSb₂Te₄亚稳相的原子结构进行了深入研究。径向分布函数G(r)显示，在GeSb₂Te₄亚稳相中几乎所有的Ge原子都为四面体构型；实验及模拟高分辨像结果表明，由于几乎所有的Ge占据Te四面体的中心，GeSb₂Te₄亚稳相形成了一种类尖晶石结构而非人们广泛接受的岩盐矿结构。

关键词：GeSb₂Te₄；亚稳相；电子显微学；径向分布函数

中图分类号：O614.43⁺1；TN304；TG115.21⁺5.3   文献标识码：A    doi:10.3969/j.issn.1000-6281.2015.05.004

The atomic structure of the GeSb₂Te₄ metastable phase

ZHU Hai-yin, SONG Jian-xiang, LIU Xian-qiang^*

（Institute of Microstructure and Properties of Advanced Materials, Beijing University of Technology, Beijing 100124，China）

Abstract: The local structures of Ge in metastable GeSbTe crystalline phases have long been concerned due to their key role in the phase transition. In this paper, the atomic structure of the GeSb₂Te₄ metastable phase was investigated by using the radial distribution function based on the electron diffraction and high resolution transmission electron microscopy. The radial distribution function G(r) reveals that almost all of Ge are located in the tetrahedral centers of Te fcc lattice in the well-developed GeSb₂Te₄ metastable phase. The high resolution transmission electron microscopy image and the corresponding simulations further indicate that a pseudo-spinel structure with tetrahedral Ge has formed, but not the generally accepted rocksalt structure.

Keywords:GeSb₂Te₄；metastable phase；transmission electron microscopy；radial distribution function

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