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

TL;DR

This paper investigates how flux states cause zero-conductance resonances in nanographite ribbon junctions, revealing sharp conductance dips linked to degenerate flux states and negative magnetoresistance.

Contribution

It uncovers the role of flux states in zero-conductance resonances and their connection to Kekulé-like current patterns in nanographite ribbons.

Findings

Zero-conductance resonances are linked to superpositions of flux states.

Resonances cause sharp conductance dips at specific energies.

Negative magnetoresistance is observed at these resonances.

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 Kekul\'e-like current patterns. These zero-conductance dips are connected with a pronounced negative magneto resistance.