Grupo de Nanomateriales, Departamento de F´ısica, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago, Chile.
J Phys Condens Matter. 2011 Dec 14;23(49):495401. doi: 10.1088/0953-8984/23/49/495401. Epub 2011 Nov 18.
First-principles molecular dynamics calculations of the structural, elastic, vibrational and electronic properties of amorphous Al(2)O(3), in a system consisting of a supercell of 80 atoms, are reported. A detailed analysis of the interatomic correlations allows us to conclude that the short-range order is mainly composed of AlO(4) tetrahedra, but, in contrast with previous results, also an important number of AlO(6) octahedra and AlO(5) units are present. The vibrational density of states presents two frequency bands, related to bond-bending and bond-stretching modes. It also shows other recognizable features present in similar amorphous oxides. We also present the calculation of elastic properties (bulk modulus and shear modulus). The calculated electronic structure of the material, including total and partial electronic density of states, charge distribution, electron localization function and the ionicity for each species, gives evidence of correlation between the ionicity and the coordination for each Al atom.
本文报道了由 80 个原子组成的超胞组成的非晶态 Al2O3 系统的结构、弹性、振动和电子性质的第一性原理分子动力学计算。对原子间相关性的详细分析使我们得出结论，短程有序主要由 AlO4 四面体组成，但与先前的结果相反，还存在大量的 AlO6 八面体和 AlO5 单元。振动态密度呈现出两个频带，与键弯曲和键拉伸模式有关。它还显示出类似非晶态氧化物中存在的其他可识别特征。我们还计算了弹性性质（体弹性模量和剪切弹性模量）。材料的计算电子结构，包括总态和部分电子态密度、电荷分布、电子局域函数和每个物种的离子性，为每个 Al 原子的离子性与配位数之间的相关性提供了证据。
