Tuning oxygen packing in silica by nonhydrostatic pressure.
Tuning oxygen packing in silica by nonhydrostatic pressure.
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DOI：
10.1103/physrevlett.99.215504
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发表时间：
2007-11
影响因子：
8.6
通讯作者：
Yunfeng Liang;C. R. Miranda;S. Scandolo
中科院分区：
文献类型：
--
作者：
Yunfeng Liang;C. R. Miranda;S. Scandolo
SiO2从低压四面体相转变为更致密的八面体相是通过氧亚晶格的坍塌而发生的。过渡路径和所得到的产品是已知的各向异性应力的存在下，这是难以控制的影响，因此解释实验结果是有问题的。基于非流体静力学分子动力学模拟，我们表明，在方石英的特定情况下，氧亚晶格的坍塌伴随着四面体单元的消失，并且可以调节非流体静力学应力以产生具有不同氧密堆积亚晶格的相，包括α-PbO 2-like相，我们为该相提供了微观形成路径，以及具有立方密堆积的相，如PbO 2，还没有在实验中看到。
The transformation of SiO2 from low pressure tetrahedral phases into denser octahedral phases takes place via the collapse of the oxygen sublattice into a close-packed arrangement. The transition paths and the resulting products are known to be affected by the presence of anisotropic stresses, which are difficult to control, so interpretation of the experimental results is problematic. Based on nonhydrostatic molecular dynamics simulations, we show that the collapse of the oxygen sublattice in the specific case of cristobalite is concomitant with the disappearance of tetrahedral units and that non hydrostatic stresses can be tuned to yield phases with different oxygen close-packed sublattices, including the alpha-PbO2-like phase, for which we provide a microscopic formation path, and phases with a cubic close packing, like anatase, not seen in experiments yet.