石墨烯纳米十字结电子输运性质

Transport Properties of Cross-junctions in Graphene Nanoribbons

利用紧束缚近似模型研究了直接型和间接型石墨烯纳米十字结的电子输运性质.扶手椅石墨烯纳米带和锯齿石墨烯纳米带交叉形成直接型结,而渐变型结相当于在直接型结的直角处增加了三角形石墨烯片.在低能区,渐变型结的三角形连接区在其锯齿型边界形成局域态,导致电导被完全拟制,并形成电导带隙;而减小三角形区的相对尺寸,或在其边界引入无序可以恢复结的金属性电导.

Transport properties of two types of cross-junctions in graphene nanoribbons are investigated by using the tight-binding model.A simple junction is formed by an armchair graphene nanoribbon crossing with a zigzag graphene nanoribbon.A deformed junction is constructed by adding graphene triangle flakes to the corners of the simple one.Within the low-energy range,localized states exist in the zigzag edges of the triangle flakes and suppress the junction conductance,thus a conductance gap is formed.The metallic conductance can be recovered by reducing the sizes of the triangle flakes or introducing disorder in the zigzag edges.