B32-LiAl点缺陷结构的第一原理计算

Study on Point Defective Structures of B32-LiAl Intermetallic Compound by First-principles Methods

采用第一原理赝势平面波方法,计算B32-LiAl金属间化合物的基本物性及其点缺陷结构的几何、能态与电子结构.通过对不同点缺陷结构形成热与形成能的计算与比较,分析和预测了B32-LiAl金属间化合物中点缺陷结构的种类与存在形式.结果表明:B32-LiAl金属间化合物的点缺陷主要是在Li子晶格上出现空位缺陷与在Al子晶格上出现反位缺陷.基于晶体总电子态密度与电荷密度分布等电子结构信息,对上述计算结果进行了初步分析.

Using a first-principles pseudopotential plane-wave method, the energetics, geometrical and electronic structures of B32-LiAl intermetallic compound and its point defective constructions are calculated. Based on the calculation and comparison on the heat of formation and the energy of formation of several point defective structures, the type and the geometrical configuration of point defects in B32-LiAl intermetallic compound are analyzed and forecasted. Resuits show that the major point defects in B32-LiAl intermetallic compound are vacancy defect in the Li sublattice or anti-site defect in the Al sublattice. In rich-Li alloy it is mainly Li anti-site defect, whereas in rich-Al alloy it is mostly Li vacancy defect. For the present calculation results, a roughly analysis is made by the electron structural information of B32-LiAl intermetallic compound that which originated from the total DOS of crystal and the total valence charge density contour plots.