▎ 摘　　要

We present a theoretical study on electronic structure and elastic transport properties of armchair graphene nanoribbon based junctions by using density functional theory calculations and nonequilibrium Green's function technique. The I-V characteristics of various junctions are examined, which all exhibit robust negative differential resistance (NDR) phenomena. It is found that such NDR behaviors originate from the interaction between the narrow density of states of the doped leads and the discrete states in the scattering region.