(昆明理工大学 云南省新材料制备与加工重点实验室，昆明 650093)
摘 要: 运用第一性原理方法计算了金属间化合物Mg2Pb的电子结构以及弹性性质，并用Voigt-Reuss-Hill方法计算得到Mg2Pb的弹性模量和切变模量。结果表明：Mg和Pb对态密度的贡献主要是Mg的2p轨道和Pb的5d轨道，其次为Mg的3s轨道和Pb的6p轨道，Pb的6s轨道贡献最小；在Mg原子周围有大量的电荷存在，呈典型的金属键特征，Mg、Pb之间存在共用的电荷，有较强的离域性，以共价键形式存在，但交界电荷的畸变不大，故共价键所占比例较少，金属键所占比例较大，Mg2Pb化合物呈半金属性；Mg2Pb的弹性模量和切变模量分别为68.6和27.9 GPa，Pugh经验判据和泊松比均表明Mg2Pb具有脆性。
关键字: 第一性原理；Mg2Pb；电子结构；弹性性质
（Key Lab of Advanced Materials of Yunnan Province, Kunming University of Science and Technology,
Kunming 650093, China）
Abstract:The electronic structure and the elastic properties of Mg2Pb were investigated by the first-principles method. The elastic modulus and shear modulus for Mg2Pb were calculated from the theoretical elastic constants by Voigt-Reuss-Hill averaging scheme. The results show that the major contribution to DOS of Mg and Pb are the 2p orbit of Mg and the 5d orbit of Pb, followed by the 3s orbit of Mg and the 6p orbit of Pb, the 6s orbit of Pb is the smallest one. There are a large number of charges around Mg, it has the characteristics of typical metal bond. Mg and Pb share some charges to form covalent bond, but the distortion of the charge at the junction is little; the proportion of covalent bond is less than the metal bond, Mg2Pb is semimetal. The elastic modulus and shear modulus of Mg2Pb are 68.6 and 27.9 GPa, respectively. Based on Pugh empirical criterions and Poisson’s ratio, Mg2Pb is brittle in nature.
Key words: first-principle; Mg2Pb; electronic structure; elastic properties
