超薄铋薄膜的量子尺寸效应

Quantum Size Effect in Ultrathin Bi Films

采用基于密度泛函理论的第一性原理方法,研究了2～16层Bi(111)薄膜的表面能和功函数,它们展现出量子尺寸效应引起的奇偶振荡。解释这种振荡需要考虑表面投影能带结构,振荡周期与量子阱态在二维布里渊区中高对称点费米能级处的穿越有关,量子阱态穿越费米能级亦引起态密度在费米能级处振荡,预示传导性质的振荡转变。

First-principles calculations of Bi（111） films up to 16 monolayers are carried out to study the oscillatory quantum size effects exhibiting in the surface energy and work function. The oscillations are correlated with the Fermi level crossings of quantum well states center at both g. and M points in the two-dimensional Brillouin zone, these crossings also lead to the density of states oscillated at Fermi surface, which indicates the conductive property will oscillate in the same manner.