Enhanced Conductance Fluctuation due to the Zero-Conductance Fano Resonances in the Quantum Point Contact on Graphene

Abstract

The electronic transport properties in graphene quantum point contacts are numerically studied. The constriction of the quantum point contact induces the zero-conductance Fano resonances in the low-energy single channel transport region near the Dirac point, i.e., perfect reflection. Randomly distributed impurities which alter the resonance energies cause large conductance fluctuation comparable to the ensemble averaged dimensionless conductance. Our results identify a further intriguing effect of impurity scattering in the electronic transport properites of graphene.