Single-channel electronic transport properties of nano-graphite ribbons

Short-range potential impurity effects on electrical conductance of nanographite ribbons are investigated by means of the Landauer approach using a tight binding model. In the low-energy regime ribbons with zigzag boundary provide a single conducting channel whose origin is connected with the presence of edge states. The conductance as a function of the chemical potential shows zero-conductance dip structures. This perfect reflectivity originates from the quasi-bound states due to the potential impurity. We find that the conductance is sensitive to the position and strength of impurity.