Jakse Noël, Bryk Taras
Univ. Grenoble Alpes, CNRS, Grenoble INP, SIMaP, F-38000 Grenoble, France.
Institute for Condensed Matter Physics of the National Academy of Sciences of Ukraine, 1 Svientsitskii Street, UA-79011 Lviv, Ukraine.
J Chem Phys. 2019 Jul 21;151(3):034506. doi: 10.1063/1.5099099.
Evolution of structure and dynamics of liquid Al with pressure along the melting line up to 300 GPa has been studied by means of ab initio molecular dynamics simulations. An analysis of structural properties shows that liquid Al undergoes uniform compression with pressure associated with a competition of the existing icosahedral local order with bcc ordering above 200 GPa. Dispersion of collective excitations indicates the presence of two branches of transverse nonpropagative modes in the second pseudo-Brillouin zone. Under pressure, the second high-frequency branch manifests as the second peak position in transverse current correlation functions, while, for ambient pressure, it corresponds to a smeared-out high-frequency shoulder. We report a correspondence of the peak locations in vibrational density of states with these two transverse collective excitations as well as their linear evolution with density.
通过从头算分子动力学模拟研究了液态铝在沿熔点线至300吉帕压力下的结构和动力学演化。对结构性质的分析表明，液态铝随着压力经历均匀压缩，这与200吉帕以上现有二十面体局部有序与体心立方有序的竞争相关。集体激发的色散表明在第二赝布里渊区存在两个横向非传播模式分支。在压力下，第二个高频分支表现为横向电流相关函数中的第二个峰值位置，而对于常压，它对应于一个展宽的高频肩部。我们报告了态密度振动中的峰值位置与这两个横向集体激发的对应关系以及它们随密度的线性演化。
