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摘要利用高温原位XAFS技术研究了半金属Sb在固态和熔态时的局域结构特点。结果表明在893K高温时固态Sb的局域结构与常温(298K)时晶态Sb的相似,但其热无序度较大。随着温度再升高20K到熔化后的913K时,熔态Sb的主配位峰形状有较大变化,其强度仅为熔化前的70%左右。这一结果表明熔化导致Sb的结构无序显著增加,我们认为这是熔态Sb中Sb原子的第一近邻配位的大部分共价键断裂造成的。模型无关的ReverseMonteCarlo方法拟合计算结果也表明熔化引起Sb样品的第一近邻配位数由固态的6增加到熔态的9。当温度升高至1058K时,Sb样品的Sb原子的径向结构函数曲线的形状与913K的Sb样品的相似,说明在熔化后的100至200K的温度范围,熔态Sb中Sb原子的局域结构差别不大。
Abstract The local structure of semi-metallic Sb in solid and molten state was studied by high-temperature in-situ XAFS technique. The results show that the local structure of solid Sb at 893K is similar to that of crystalline Sb at room temperature (298K), but the thermal disorderedness is larger. As the temperature increases again from 20K to 913K after melting, the main coordination peak shape of the molten Sb has a great change, its intensity is only about 70% before melting. This result shows that the melting leads to a significant increase in the structural disorder of Sb, which we believe to be caused by the majority of the covalent bonds breaking of the first neighbor of the Sb atom in the molten Sb. The fitting of the model-independent ReverseMonteCarlo method also shows that the melting results in the increase of the first-neighbor coordination number of the Sb sample from the solid 6 to the molten 9. When the temperature is raised to 1058K, the shape of the radial structure curve of the Sb atom of the Sb sample is similar to that of the 913K Sb sample, indicating that in the temperature range of 100 to 200K after melting, the local Little difference in structure.