Harbin Institute of Technology, Harbin, 150080, China.
Center for High Pressure Science and Technology Advanced Research, Changchun, 130015, Beijing, 100094, China.
Sci Rep. 2017 Jul 18;7(1):5666. doi: 10.1038/s41598-017-05985-8.
In situ high energy X-ray pair distribution function (PDF) measurements, microtomography and reverse Monte Carlo simulations were used to characterize the local structure of liquid gallium up to 1.9 GPa. This pressure range includes the well-known solid-solid phase transition from Ga-I to Ga-II at low temperature. In term of previous research, the local structure of liquid gallium within this domain was suggested a mixture of two local structures, Ga I and Ga II, based on fitting experimental PDF to known crystal structure, with a controversy. However, our result shows a distinctly different result that the local structure of liquid gallium resembles the atomic arrangement of both gallium phase II and III (the high pressure crystalline phase). A melting mechanism is proposed for Ga, in which the atomic structure of phase Ι breaks up at the onset of melting, providing sufficient free volume for atoms to rearrange, to form the melt.
采用原位高能 X 射线对分布函数 (PDF) 测量、微断层扫描和反向蒙特卡罗模拟，对高达 1.9GPa 的液态镓的局部结构进行了研究。该压力范围包括低温下众所周知的 Ga-I 到 Ga-II 的固-固相变。根据以往的研究，在这个范围内，液态镓的局部结构被认为是两种局部结构 Ga I 和 Ga II 的混合物，这是基于将实验 PDF 拟合到已知晶体结构的基础上得出的，存在争议。然而，我们的结果显示出明显不同的结果，即液态镓的局部结构类似于 Ga 相 II 和 III（高压晶相）的原子排列。提出了一种 Ga 的熔化机制，其中相 Ι 的原子结构在熔化开始时分解，为原子重新排列提供了足够的自由体积，从而形成熔体。
