Effects of Geometry and Symmetry on Electron Transport through Graphene–Carbon-Chain Junctions
Effects of Geometry and Symmetry on Electron Transport through Graphene–Carbon-Chain Junctions
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DOI：
10.1021/jp405318b
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发表时间：
2013-09
影响因子：
3.7
通讯作者：
Yaojun Dong;Xuefeng Wang;M. Zhai;Jian-chun Wu;Liping Zhou;Q. Han;Xue-Mei Wu
中科院分区：
文献类型：
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作者：
Yaojun Dong;Xuefeng Wang;M. Zhai;Jian-chun Wu;Liping Zhou;Q. Han;Xue-Mei Wu
采用非平衡绿色函数方法结合密度泛函理论研究了碳原子链连接的锯齿形石墨烯纳米带（ZGNR）之间的电子输运.碳链中轨道的对称性严格地选择了传输电子的模式和能量。费米能级附近的电子输运可以很好地通过与纳米带接触的碳链的位置和数量来控制。在由中心碳链连接的对称ZGNR中，在费米能处出现方形电导台阶，因为它下面的反对称模不允许通过该链。如果在连接中添加侧碳链，这些模式可以另外有助于电导。通过选择合适的几何结构，可以在器件中实现欧姆接触、稳流或负微分电阻现象。
The electron transport between two zigzag graphene nanoribbons (ZGNRs) connected by carbon atomic chains has been investigated by the nonequilibrium Green’s function method combined with the density functional theory. The symmetry of the orbitals in the carbon chain critically selects the modes and energies of the transporting electrons. The electron transport near the Fermi energy can be well-manipulated by the position and the number of carbon chains contacting the nanoribbons. In symmetric ZGNRs connected by a central carbon chain, a square conductance step appears at the Fermi energy because the antisymmetric modes below it are not allowed to go through the chain. These modes can additionally contribute to the conductance if side carbon chains are added in the connection. By choosing a proper geometry configuration, we can realize Ohmic contact, current stabilizer, or the negative differential resistance phenomenon in the devices.