Robust conductance zeroes in graphene quantum dots and other bipartite systems

TL;DR

This paper demonstrates that conductance zeroes can occur in bipartite systems like graphene quantum dots at half-filling when leads connect to different sublattices, and these zeroes are robust against impurities.

Contribution

It introduces a theoretical framework showing conductance zeroes in bipartite systems at half-filling with specific lead configurations, applicable to graphene quantum dots.

Findings

Conductance zeroes occur at half-filling when leads contact different sublattices.

Zeroes are robust against single-site impurities.

Application to graphene quantum dots confirms theoretical predictions.

Abstract

Within the Landauer transport formalism we demonstrate that conductance zeroes are possible in bipartite systems at half-filling when leads are contacted to different sublattice sites. In particular, we investigate the application of this theory to graphene quantum dots with leads in the armchair configuration. The obtained conductance cancellation is robust in the presence of any single-site impurity.