碱金属在磷烯表面吸附和迁移行为的第一性原理研究

First-principles study of adsorption and diffusion properties of alkali metaladatoms on phosphorene

利用基于密度泛函理论的平面波赝势方法研究了碱金属(Li、Na、K)-磷烯体系,分析了体系的吸附性质、电学性质和迁移行为.结果表明:碱金属在磷烯表面的最稳定吸附位都是H位.吸附过程中电荷由碱金属原子转移到磷烯,碱金属-磷烯体系表现出一定的离子性.碱金属-磷烯体系的吸附能从大到小为ΔE_(Li-磷烯)ΔE_(K-磷烯)ΔE_(Na-磷烯).Li→Na→K,随着原子序数的递增,体系的离子性逐渐增强;碱金属原子越来越容易在磷烯表面迁移.

The alkali metal adatom（ Li,Na,K）-phosphorene systems were studied using the plane wave pesudopotential method based on density functional theory（ DFT）. The adsorption,electronic and diffusion properties for alkali metal-phosphorene systems were calculated. Alkali adatoms prefer to adsorb at the H site of phosphorene. The charge transfers from alkali metal adatoms to phosphorene. The alkali metal adatom-phosphorene systems exhibit ionic property. The adsorption energy from low to high is ΔE（Li-phosphorene） ΔE（K-phosphorene）ΔE（Na-phosphorene）. Li→Na→K,the degree of ionic property of alkali metal-phosphorene systems increases with the increasing atomic number of alkali metal atom. The decrease in diffusion energy indicates that diffusion behavior of alkali metal adatoms on the surface of phosphorene is more and more easy.