二维BC2 N薄片的结构稳定性和电子性质

采用基于密度泛函理论的第一性原理方法,对二维BC₂N薄片的结构稳定性和电子性质进行了系统的研究.计算了BC₂N化合物16种可能的二维单层结构.对它们的能带结构分析发现,对称性最高的构型与石墨烯一样是一种半金属,而其他二维结构则为有不同带隙的半导体,其中最稳定的构型是带隙值为1.63 eV的直接带隙半导体.对最稳定构型的差分电荷密度分析和Bader分析发现:在最稳定的构型中,C–C键、C–N键、C–B键和B–N键主要以共价键的形式呈现,也具有比较明显的离子性.在应力作用下最稳定构型的单层BC₂N的带隙宽度会发生变化,压缩时带隙变宽,而拉伸时带隙变窄,但仍然为直接带隙半导体. 关键词： 2N')" href="#">BC₂N 单层原子薄片 电子结构 从头计算

The structural stability and electronic properties of monolayer BC2N

The structural stability and the electronic properties of two-dimensional monolayer BC₂N are studied by employing the first principles method based on the density functional theory. 16 polymorphic structures of monolayer BC₂N are calculated. Analysis of the 16 band structures suggests that the structure with the highest symmetry is of a semimetal which is the same as graphene. All the other structures are of semiconductors with different band gaps, of which the most stable structure is of semiconductor with a direct gap of 1.63 eV. Based on the deformation charge density and the Bader analysis, the bonds C-C, C-N, C-B, and B-N in the most stable monolayer BC₂N are mainly covalent, however, they present also significant ionic behaviors. Exerting a stress on the monolayer BC₂N sheet changes the band gap, showing that the band gap increases during the compression while decreases during the stretch, and the system keeps a direct semiconductor.