Eur. Phys. J. B (2012) 85: 121
https://doi.org/10.1140/epjb/e2012-21013-8

Regular Article

Electronic transport for impurity-doped armchair-edge graphene nanoribbons

¹ Department of Physics and Key Laboratory for Low-Dimensional Quantum Structures and Manipulation (Ministry of Education), Hunan Normal University, 410081 Changsha, P.R. China
² Department of Physics, Shaoyang University, 422001 Shaoyang, P.R. China
³ Department of Physics and Electronic Information Science, Huaihua University, 418008 Huaihua, P.R. China

^a e-mail: ghzhou@hunnu.edu.cn

Received: 10 December 2011
Received in final form: 13 February 2012
Published online: 13 April 2012

Abstract

We investigate the electronic transport for an impurity-doped armchair-edge graphene nanoribbon (AGNR), with 7 or 8 dimer lines along zigzag direction, sandwiched between two normal leads. By using the standard nonequilibrium Green’s function technique, it is demonstrated that, the impurity influence on the transport properties for system with semiconducting 7-AGNR system is more sensitive than that for one with metallic 8-AGNR system in the vicinity of the impurity energy level. In particular, in the absence of impurity the density of states (DOS) and linear conductance G possess a small zero value interval for 7-AGNR system and a large nonzero plateau for 8-AGNR one, respectively. Interestingly, as impurity included the DOS and G show a single sharp resonant peak around the impurity energy level for 7-AGNR system due to resonant tunneling, while a small dip appears in the same position for 8-AGNR system due to the antiresonance states. Moreover, we have also inspected the behavior of the differential conductance upon varying the impurity concentration for the systems. The findings here may suggest it is more favorable to fabricate an electric switch with high on-off ratio by using an impurity-assisted semiconducting AGNR.