Mg在Si(220)表面吸附的第一性原理计算

First principles calculation of Mg adsorption on Si(220) surface

采用基于密度泛函理论的第一性原理平面波赝势的方法,通过搜寻Mg原子在硅Si(220)晶面上的最佳吸附位置,计算Mg/Si(220)体系的吸附能、电子态密度、电子布居和功函数等,系统研究了Mg原子在Si(220)表面的吸附过程.结果表明:Si表面Mg原子的最稳定吸附位置为Si(220)晶面的穴位,此时吸附能最低.同时,Mg/Si(220)体系中Mg原子的2p和3s轨道电子与Si原子的3s和3p轨道电子间的强相互作用使体系的电子布居和功函数发生改变.

The process of Mg adsorption on the Si(220)surface was investigated by calculating the adsorption energies,densities of states(DOS),electron populations and work functions using first-principles based on the density functional theory(DFT)with the plane wave pseudo potential method to search for the optimal adsorption sites of Mg atom on Si(220)crystal surface.The results show that the most stable site of Mg atom on the Si(220)surface is the hollow site of crystal surface,where the system has the lowest adsorption energy.At the same time,the interaction between 2 p,3 s states of Mg atom and 3 s,3 p states of Si atom in the Mg/Si(220)system changes the electron populations and work function of the system.