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采用第一性原理赝势平面波方法,计算并详细分析了面心立方Cu晶体及其(100),(1lO)和(111)这3个低指数表面的原子结构、表面能量及表面电子态密度.表面能的计算结果表明,Cu(111)表面的结构稳定性最好,Cu(100)表面次之,Cu(110)表面的结构稳定性最差.3个表面的表面原子弛豫量随着层数的增加而逐渐减弱.Cu(110)表面的最表层原子相对收缩最大,Cu(100)表面次之,Cu(111)表面的最表层原子相对收缩最小.表面原子弛豫不仅引起表面几何结构的变化,而且使表面层原子的电子态密度峰形相对晶体内部发生变化,这是表面能产生的主要原因,而Cu(11O)表面相对于Cu(100)与Cu(111)表面具有高表面活性的主要原因则源于其表面层原子电子态密度在高能级处的波峰相对晶体内部显著的升高.
The first-principles pseudopotential plane-wave method was used to calculate and analyze the atomic structure, surface energy and surface density of surface-centered cubic Cu crystals and their (100), (1lO) and (111) . The calculation of surface energy shows that the structural stability of Cu (111) surface is the best, the Cu (100) surface is the second, and the structural stability of Cu (110) (110), the relative contraction of Cu (111) surface is the largest, followed by that of Cu (100) surface, and the relative contraction of the surfacemost Cu (111) (100) and Cu (111) surfaces of the Cu (100) and Cu (111) surfaces, respectively. The change of the geometrical structure and the change of the peak shape of the electronic density of states of the surface layer atoms with respect to the interior of the crystal are the main causes of the surface energy. The main reason for the high surface activity is due to the significant increase of the peak at the higher energy level relative to the interior of the crystal.