Zero-Conductance Resonances due to Flux States in Nanographite Ribbon Junctions

Abstract

The electronic transport properties through junctions in nanographite ribbons are investigated using the Landauer approach. In the low-energy regime ribbons with zigzag boundary have a single conducting channel of edge states. The conductance as a function of the chemical potential shows a rich structure with sharp dips of zero conductance. Each zero-conductance resonance is connected with a resonant state which can be interpreted as the superposition of two degenerate flux states with Kekulé-like current patterns. These zero-conductance dips are connected with a pronounced negative magneto resistance.

4 pages, 2 figures: published in Phys. Rev. Lett. minor changes in text, figures and references