扶手椅型石墨纳米带的双空位缺陷效应研究

The divacancy-defect effect of armchair graphene nanoribbons

采用基于密度泛函理论的第一性原理电子结构和输运性质计算,研究了扶手椅型石墨纳米带(具有锯齿边缘)的双空位缺陷效应.研究发现:双空位缺陷的存在并没有改变石墨纳米带的金属特性,但改变了费米面附近的能带结构.同时,双空位缺陷的取向对石墨纳米带的输运性质有很重要的影响.对于奇数宽度的纳米带,斜向双空位缺陷使得石墨带导电性能减弱,而垂直双空位能基本保留原有的线性伏安特性,导电性能降低较少;对于偶数宽度的纳米带,斜向双空位缺陷会使石墨带导电性能明显增强,而垂直双空位缺陷则具有完整石墨带的输运性质.

By using first-principles electronic structure and transport calculations based upon the density functional theory, we have studied the divacancy-defect effect of armchair graphene nanoribbons with zigzag edges. It is shown that the existence of 585 divacancy defects do not change the metallic characteristics of graphene nanoribbon, while changing the energy band structures near the Fermi energy level. Moreover, the spatial orientations of the divacancy defects have obvious effect on the transport properties of armchair graphene nanoribbons： for armchair graphene nanoribbons with odd width, slanting divacancies defects weaken conducting performace of graphene nanoribbons, while graphene nanoribbons with vertical divacancies defects basically remain linear I-V characteristics and little decrease in conducting capacity;For armchair graphene nanoribbons with even width, inclined divacancy defects increase the conducting property of graphene nanoribbous, while graphene nanoribbons with vertical divacancy defects have I-V characteristics of the perfect graphene nanoribbons.