Density-driven structural transformations in B2O3 glass
Density-driven structural transformations in B2O3 glass
复制标题
B2O3 玻璃中密度驱动的结构转变
DOI：
10.1103/physrevb.90.024206
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发表时间：
2014
影响因子：
3.7
通讯作者：
M. Micoulaut
中科院分区：
文献类型：
--
作者：
A. Zeidler;Kamil Wezka;Dean A. J. Whittaker;P. Salmon;A. Baroni;S. Klotz;H. Fischer;M. Wilding;C. Bull;M. Tucker;M. Salanne;G. Ferlat;M. Micoulaut
用原位高压中子衍射法研究了B2O_3玻璃在常压至17.5(5)Gpa范围内压缩时的结构。实验结果得到了用新发展的非球面离子模型进行的分子动力学模拟的补充。这些结果与其他实验技术得到的结果联系在一起，揭示了三种致密化过程。在第一种情况下，当压力从常压增加到6.3(5)Gpa时，BO_3三角形是主要的结构基元，但与硼氧环的溶解有关的中程有序发生了变化。在第二种情况下，在超过6.3 GPA的压力下，BO4基序取代B03三角形，而硼氧环的溶解继续进行，直到在11-14 GPa时完成溶解。在第三个过程中，B-O配位数随着压力的增加而继续增加，以获得主要的四面体玻璃，这个过程是在超过22.5 Gpa的压力下完成的。当玻璃从8.2 GPA的压力恢复到环境中时，恢复了三角形的BO_3基元，但相对于未压缩的材料，中程有序发生了变化。实验和模拟的比较表明，非球面离子模型能够在至少10 Gpa的压力下提供前所未有的精度。
The method of in situ high-pressure neutron diffraction is used to investigate the structure of B2O3 glass on compression in the range from ambient to 17.5(5) GPa. The experimental results are supplemented by molecular dynamics simulations made using a newly developed aspherical ion model. The results tie together those obtained from other experimental techniques to reveal three densification regimes. In the first, BO3 triangles are the predominant structural motifs as the pressure is increased from ambient to 6.3(5) GPa, but there is an alteration to the intermediate range order which is associated with the dissolution of boroxol rings. In the second, BO4 motifs replace BO3 triangles at pressures beyond 6.3 GPa and the dissolution of boroxol rings continues until it is completed at 11–14 GPa. In the third, the B-O coordination number continues to increase with pressure to give a predominantly tetrahedral glass, a process that is completed at a pressure in excess of 22.5 GPa. On recovery of the glass to ambient from a pressure of 8.2 GPa, triangular BO3 motifs are recovered but, relative to the uncompressed material, there is a change to the intermediate range order. The comparison between experiment and simulation shows that the aspherical ion model is able to provide results of unprecedented accuracy at pressures up to at least 10 GPa.