Institute of Microstructure and Property of Advanced Materials, Beijing University of Technology, Beijing 100022, China.
Phys Rev Lett. 2011 Jan 14;106(2):025501. doi: 10.1103/PhysRevLett.106.025501. Epub 2011 Jan 13.
Using electron microscopy and diffraction techniques, as well as first-principles calculations, we demonstrate that as much as 35% of the total Ge atoms in the cubic phase of Ge2Sb2Te5 locate in tetrahedral environments. The Ge-vacancy interactions play a crucial stabilizing role, leading to Ge-vacancy pairs and the sharing of vacancies that clusters tetrahedral Ge into domains. The Ge2Sb2Te5 structure with coexisting octahedral and tetrahedral Ge produces optical and structural properties in good agreement with experimental data and explains the property contrast as well as the rapid transformation in this phase-change alloy.
利用电子显微镜和衍射技术以及第一性原理计算，我们证明在四方相 Ge2Sb2Te5 中，多达 35%的总 Ge 原子位于四面体环境中。Ge 空位相互作用起着至关重要的稳定作用，导致 Ge 空位对和空位共享，将四面体 Ge 团簇成畴。具有共存八面体和四面体 Ge 的 Ge2Sb2Te5 结构产生的光学和结构性质与实验数据非常吻合，并解释了这种相变合金的性能对比以及快速转变。
