Al(111)表面单个Al原子的操纵── W针尖与Al原子的相互作用

THE MANIPULATION OF A SINGLE Al ATOM ON Al(111) SURFACE  THE INTERACTION BETWEEN THE W TIP AND Al ATOM

为了较清楚地阐明扫描隧道显微镜针尖在样品表面原子操纵中的具体作用，根据第一性原理的离散变分理论计算，采用“团簇模型”研究了在无外加电场下，Ｗ针尖与样品Ａｌ（１１１）表面Ａｌ原子的相互作用．结果表明：随着Ｗ针尖与样品表面接近到一定程度（针尖与样品表面的距离Ｓ≤１０ａ．ｕ．（０５３ｎｍ））时，由于针尖原子与样品表面原子的相互作用，使位于针尖正下方的表面Ａｌ原子在脱离表面时感受到一稳定的势阱，即在无外场的情况下，当Ｗ针尖与样品Ａｌ（１１１）表面接近到一定程度时，由于针尖的吸引作用，将使针尖正下方的Ａｌ原子自动离开样品表面而移向Ｗ针尖，实现Ａｌ（１１１）表面单个Ａｌ原子的操纵．

Abstract In order to elucidate the action of the STM tip in the manipulation of atom on a sample surface,the interaction between W tip atom and sample Al(111) surface atom is studied with cluster model by employing the first principles method——discrete variational method.The calculated results show that if the distance S between the tip and sample surface is short enough ( S ≤10a.u.),when the sample surface Al atom,which is just under the W tip,escapes from the surface,it fells a stable potential well.This indicates that even without an external field,the Al atom can be extracted from the sample surface to the tip by the attraction of the W tip,if the tip is very close to the sample surface.