Electronic structure and transport of a carbon chain between graphene nanoribbonleads

Abstract

The electronic structure and transport property of a carbon chain between two graphenenanoribbon leads are studied using an ab initio tight-binding (TB) model and Landauer’sformalism combined with a non-equilibrium Green’s function. The TB Hamiltonian andoverlap matrices are extracted from first-principles density functional calculations throughthe quasi-atomic minimal basis orbital scheme. The accuracy of the TB model isdemonstrated by comparing the electronic structure from the TB model with that fromfirst-principles density functional theory. The results of electronic transport on a carbonatomic chain connected to armchair and zigzag graphene ribbon leads, such asdifferent transport characters near the Fermi level and at most one quantizedconductance, reveal the effect of the electronic structure of the leads and the scatteringfrom the atomic chain. In addition, bond length alternation and an interestingtransmission resonance are observed in the atomic chain connected to zigzaggraphene ribbon leads. Our approach provides a promising route to quantitativeinvestigation of both the electronic structure and transport property of large systems.