晶格反演法构建SiC/Mg界面对势及其验证

摘要

通过分析SiC和Mg的晶体结构,构造了SiC与Mg的共格晶面.采用Chen-M(o)bius晶格反演法对SiC/Mg界面的原子对势进行了反演,分别推导了Si和Mg原子、C和Mg原子间作用势与界面结合能关系的解析表达式.在此基础上,从头计算了SiC/Mg界面的结合能曲线,结合反演公式得到了Si和Mg原子、C和Mg原子的对势函数,并对反演过程的自洽性进行了检验.此外,建立了其他6种不同的SiC/Mg界面构型,通过对比反演对势计算的界面结合能与从头计算的结果,对反演所得对势的可转移性进行了验证.结果表明:从头计算的界面结合能可以由反演对势精确地算出,整个反演过程和结果是自洽的,所得原子对势同样适用于其他界面构型,具有良好的可转移性.本文推导的反演公式同样适用于与SiC/Mg界面结构相似的其他界面原子对势的研究.%The coherent interface of Mg and SiC was established by analyzing their crystal structures.Interatomic pair potentials for SiC/Mg interfaces were inversed by Chen-M(o)bius lattice inversion method and analytical expressions for Si-Mg and C-Mg pair potentials as a function of the SiC/Mg interfacial adhesive energy have been derived,respectively.On this basis,ab initio calculations of the adhesive energy for the SiC/Mg interface were carried out.Thus,the Si-Mg and C-Mg pair potentials were obtained by the inversion formula.In addition,a self-consistent check was conducted to validate the inversion process.Meanwhile,six other SiC/Mg interface models were built to validate the transferability of the inversed pair potentials by comparing adhesive energies predicted by the ab initio method with those calculated by the inversion method.The results show that the original ab initio adhesive energies can be precisely reproduced by the inversed potentials,indicating that the inversion method is self-consistent and the obtained potentials are of good transferability for some other interface models.The inversion formula deduced in this paper is also suitable for other interfaces similar to SiC/Mg interface structures.