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通过一种空位模型详细的描述了In在Al(001)表面的扩散偏析过程,利用周期性密度泛函理论方法计算了这个偏析过程中每步构型的能量和In原子扩散的能量壁垒,并对可能的偏析机理进行分析.结果表明:In原子从Al(001)表面第二层扩散偏析至表面层时,系统的能量降低了0.64eV,最大的扩散迁移壁垒为0.34eV;而从表面更内层向表面第二层扩散时系统能量基本保持不变,扩散需要克服的能量壁垒为0.65eV,说明In原子在Al(001)表面只能由体内向表面扩散偏析.In在Al(001)的清洁表面具有强烈的偏析趋势,在热力学上是容易进行的.
The diffusion process of In on Al (001) surface is described in detail by a kind of vacancy model, and the energy barrier of each configuration energy and In atom diffusion in this segregation process is calculated by periodic density functional theory The possible segregation mechanism is analyzed. The results show that when In atoms diffuse from the second layer of Al (001) surface to the surface layer, the energy of the system decreases by 0.64eV and the maximum barrier of diffusion and migration is 0.34eV. The energy of the system to be overcome is 0.65eV, indicating that the In atom can only be segregated from the body to the surface on the Al (001) surface. In the Al (001) The cleansing surface has a strong segregation tendency and is thermodynamically easy to carry out.