Z形石墨带的电子输运性质: 形状与尺寸效应

基于格林函数方法及Landauer-Büttiker公式, 研究了纳米石墨带异质结的电子输运性质, 石墨带异质结由Z 形石墨带与两个锯齿型石墨带电极构成. 研究发现电导大小依赖其几何构型. 由于电子局域在锯齿型石墨带边缘, 因此在费米能级附近出现了电导隙或电导谷. 调节结间石墨带的宽度, 发现准束缚态的存在诱导许多尖锐的电导峰, 电导峰的数目几乎与结间的石墨带长度无关. 在低能区, 当θ为60°或150°时, 宽度均匀的Z型石墨带仍然保持弹道输运特征. 因此, Z形纳米石墨带可选择地应用于未来的纳微电路.

Electronic Transport in Z-Shaped Graphene-Nanoribbons:Shape and Size Effects

Based on the Green's function method and the Landauer-Bǖttiker formula, we studied the electronic transport properties of a graphene heterojunction. This was a Z-shaped graphene nanoribbon (GNR), which was connected by zigzag graphene nanoribbon leads. We show that the conductance of the Z-shaped GNRs is highly sensitive to the shape and size of the heterojunctions. The charge density is strongly localized on the zigzag edge sites of the leads and thereby a conductance dip or gap results at the Fermi energy. By varying the width of the graphene ribbons between the junctions, we found many more resonant peaks in the conduction because of the quasi-bound states. The number of resonant peaks has little to do with the length of the graphene ribbons between the junctions. Importantly, we show that in the low-energy region the electrons retain their ballistic transport characteristic in the width uniformity of Z-shaped GNRs with included angle 9 of 60° or 150° turns. These findings show that the Z-shaped GNRs can be selected for future ballistic device applications.