第一性原理研究3C-SiC/Mg复合材料界面的电子结构

First-principles study of the electronic structure of the 3C-SiC/Mg composite interface

基于密度泛函理论的第一性原理平面波赝势方法对4种3C-SiC(111)/Mg(0001)界面模型进行研究.界面间距和粘附功的计算表明,结构优化之后的界面模型只在z轴方向发生了移动,界面间距发生了不同程度的缩短;中心型模型的稳定性强于顶位型模型,C终端结构的稳定性强于Si终端结构,中心型C终端的界面模型具有最大的粘附功(2.5834 J/m^(2))和最小的界面间距(1.7193Å),是4种模型中最稳定的结构. Mulliken电荷、电荷密度分布、差分电荷密度和态密度的计算表明,中心性结构的Si终端和C终端模型界面处存在共价键、离子键和金属键.

Four kinds of 3 C-SiC(111)/Mg(0001)interface models were studied using the first-principle plane wave pseudopotential method based on density functional theory. The calculation of interface spacing and adhesion work shows that the interface model after structural optimization only moves in the Z-axis direction, and the interface spacing is shortened to varying degrees;The stability of the center-site model is stronger than that of the top-site model, and the stability of the C-terminated structure is stronger than that of the Si-terminated structure. The interface model of the center-site C-terminated has the maximum adhesion work(2.5834 J/m^(2)) and the minimum interface spacing(1.7193 Å), which is the most stable structure among the four models. The calculation of Mulliken population, charge density distribution, charge density difference and density of states shows that there are covalent bonds, ionic bonds and metallic bonds at the interface of Si-terminated and C-terminated models of center-site structure.