非均匀电势和子晶格势调控下扶手型石墨烯纳米带的电子特性

Manipulating Electronic Properties of the Armchair Graphene Nanoribbons by Nonuniform Electric Potential and Sublattice Potential

扶手型石墨烯纳米带,由于其纳米带宽度的差异,可以分为金属型与半导体型.本文主要研究非均匀电势和子晶格势作用下扶手型石墨烯纳米带的电子特性.我们发现当只有子晶格势作用时,不同类型的扶手型石墨烯纳米带的能隙随子晶格势的增大基本呈线性增长.然而不同类型的扶手型石墨烯纳米带的能隙随非均匀电势的增大却呈现出不同的变化趋势.对于金属型的情况,在非均匀电势和子晶格势共同调控下,可以实现能隙的打开与闭合.最后,在纳米带上施加垂直磁场,两端电导表现出有趣的量子演化行为.

The armchair graphene nanoribbons can be either semiconducting or metallic, depending on their widths. In this paper, we study the electronic properties of the armchair graphene nanoribbons manipulated by nonuniform electric potential and sublattice potential. We find that the bulk gap increases gradually with the increase of the sublattice potential whereas the bulk gap exhibits a different trend with the increase of nonuniform electric potential for different types of armchair graphene nanoribbons. For the metallic case,the bulk gap can display opening and closing behaviour under both nonuniform electric potential and sublattice potential. Finally, an interesting quantized evolution behaviour of two-terminal conductance is obtained by applying a perpendicular magnetic field.