▎ 摘　　要

The transport properties of armchair graphene nanoribbons with two structural nanoconstrictions are studied by atomistic simulations. With the appropriate geometry and size, the central region between the two constrictions can behave as a single tunneling quantum dot. Within the low energy range around the Dirac point, the conductance of the structure shows strong resonances that are related to the quasi-bound states localized in the dot. The quasi-bound states are associated with the standing waves confined by the two constrictions, and can be effectively modulated by the geometric parameters of the structure. (C) 2011 American Institute of Physics. [doi:10.1063/1.3592204]