Cluster modeling of quasi‐adaptive phases in vitreous germanium selenides
Cluster modeling of quasi‐adaptive phases in vitreous germanium selenides
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DOI：
10.1002/pssc.200982810
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发表时间：
2010-04
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通讯作者：
O. Shpotyuk;R. Golovchak;V. Boyko;S. Kozyukhin
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作者：
O. Shpotyuk;R. Golovchak;V. Boyko;S. Kozyukhin
利用RHF/6-311G*基集建立了基于ab-initio计算的聚类建模方法，证明了二进制Gex Se100-x系统在20≤x < 26域内不存在中间最优约束相位。结果表明，在预期的可逆性窗口内，所有玻璃组分的“支腿筏”骨架特征都是守恒的。因此，二元Gex Se100-x玻璃的结构在x < 12时可描述为“链交叉”模型，在12≤x < 20时可描述为“链交叉”和“支臂筏”混合模型，在x≥20时可描述为修正的“支臂筏”模型。二元Gex Se100-x玻璃的预期可逆性窗口被证明仅为准自适应相，基于“伸出臂式”结构动机，两个边缘和四个角共享四面体由最佳约束的Ge-Se-Se-Ge桥连接，额外的Se原子以环状构型取代Se-Se二聚体。该系统的高分辨率x射线光电子能谱测量结果很好地证实了量子力学建模的结果。（©2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim）
The developed cluster modeling approach based on ab-initio calculations with RHF/6-311G* basis set testifies absence of intermediate optimally-constrained phase in binary Gex Se100-x system within 20 ≤ x < 26 domain. It is shown, that character “outrigger raft” carcass is conserved for all glass compositions within expected reversibility window. Thus, the structure of binary Gex Se100-x glasses can be described in terms of “chains crossing” model in case of x < 12, mixed “chains crossing” and “outrigger raft” models in case of 12 ≤ x < 20 and modified “outrigger raft” model in case of x ≥ 20. The expected reversibility window in binary Gex Se100-x glasses is shown to be only quasi-adaptive phase, based on “outrigger raft” structural motive with two edge- and four corner-sharing tetrahedra interconnected by optimally-constrained Ge-Se-Se-Ge bridges with extra Se atoms in ring-like configurations replaced Se-Se dimers. The results of quantum mechanics modeling are confirmed well by high-resolution X-ray photoelectron spectroscopy measurements in this system. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)