title: Semiconducting states and transport in metallic armchair-edged graphene nanoribbons.
abstract: Based on the nonequilibrium Green's function method within the tight-binding approximation scheme, through a scanning tunneling microscopy (STM) model, we study the low-energy electronic states and transport properties of carbon chains in armchair-edged graphene nanoribbons (AGNRs). We show that semiconducting AGNRs possess only semiconducting chains, while metallic ones possess not only metallic chains but also unconventional semiconducting chains located at the 3 jth (j ≠ 0) column from the edge (the first chain) due to the vanishing of the metallic component in the electron wavefunction. The two types of states for carbon chains in a metallic AGNR system are demonstrated by different density of states and STM tunneling currents. Moreover, a similar phenomenon is predicted in the edge region of very wide AGNRs. However, there is remarkable difference in the tunneling current between narrow and wide ribbons.
authors.affiliation: Department of Physics and Key Laboratory for Low-Dimensional Structures and Quantum Manipulation (Ministry of Education), Hunan Normal University, Changsha 410081, People's Republic of China.
authors.forename: Xiongwen
authors.initials: X
authors.lastname: Chen
authors.forename: Haiyan
authors.initials: H
authors.lastname: Wang
authors.forename: Haiqing
authors.initials: H
authors.lastname: Wan
authors.forename: Kehui
authors.initials: K
authors.lastname: Song
authors.forename: Guanghui
authors.initials: G
authors.lastname: Zhou