The Structure of Liquid and Amorphous Hafnia
The Structure of Liquid and Amorphous Hafnia
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DOI：
10.3390/ma10111290
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发表时间：
2017-11-01
期刊：
影响因子：
3.4
通讯作者：
Benmore, Chris J.
中科院分区：
文献类型：
--
作者：
Gallington, Leighanne C.;Ghadar, Yasaman;Benmore, Chris J.
了解无定形固体的原子结构对于预测和调整它们的宏观行为很重要。在这里，我们使用高能X射线衍射，中子衍射和分子动力学模拟相结合的基准在高温稳定的液体和低密度的非晶固体状态的Al 2 O3的原子相互作用。衍射结果显示，在所研究的液体和无定形纳米颗粒形式中存在类似于7的平均Hf-O配位数。测得的对分布函数进行比较，从文献中的几个模拟模型产生的。我们还进行了从头算和经典的分子动力学模拟，表明密度有很强的影响多面体的连接。液相中Hf-Hf相互作用分布较宽，而低密度非晶纳米团簇的形成可以重现实验中观察到的Hf-Hf部分对分布函数中的尖锐分裂峰。从气相凝聚的无定形纳米粒子的团聚与形成的边缘共享和角共享HfO 6，7多面体类似于在单斜相观察到的。
Understanding the atomic structure of amorphous solids is important in predicting and tuning their macroscopic behavior. Here, we use a combination of high-energy X-ray diffraction, neutron diffraction, and molecular dynamics simulations to benchmark the atomic interactions in the high temperature stable liquid and low-density amorphous solid states of hafnia. The diffraction results reveal an average Hf-O coordination number of similar to 7 exists in both the liquid and amorphous nanoparticle forms studied. The measured pair distribution functions are compared to those generated from several simulation models in the literature. We have also performed ab initio and classical molecular dynamics simulations that show density has a strong effect on the polyhedral connectivity. The liquid shows a broad distribution of Hf-Hf interactions, while the formation of low-density amorphous nanoclusters can reproduce the sharp split peak in the Hf-Hf partial pair distribution function observed in experiment. The agglomeration of amorphous nanoparticles condensed from the gas phase is associated with the formation of both edge-sharing and corner-sharing HfO6,7 polyhedra resembling that observed in the monoclinic phase.