Dependence of transport property of graphene nanoribbon on contacts: Electron-hole symmetry and conductance at the Dirac point

Our investigation of the transport properties in graphene nanoribbon's (GNR) between quantum wire contact and decoupled chains contact confirms general predictions for the transport through GNR for specific geometries. We found that electron-hole (e-h) symmetry depends sensitively on the contact and interface. For quantum wire contacts, the breaking of e-h symmetry occurs in armchair GNR due to odd-numbered ring at the interface, and at Dirac point the maximal transmission corresponds to the momentum k(y) = 2 pi/3 root 3a (a = 0.142 angstrom). The spatial density of states of armchair GNR is shown. Furthermore, the conductance at Dirac point is independent of contacts with dense modes. (C) 2011 Elsevier B.V. All rights reserved.