Point-Contact Conductance in Asymmetric Chalker-Coddington Network Model

TL;DR

This paper introduces an asymmetric Chalker-Coddington network model to study point-contact conductance in disordered 2D electron systems with a conducting channel, revealing unique conductance behavior relevant to systems like zigzag graphene nanoribbons.

Contribution

It presents a novel asymmetric network model and demonstrates its distinct conductance properties compared to symmetric models, with implications for specific physical systems.

Findings

Broad conductance distribution at large contact distances

Non-trivial power law dependence of average conductance on system width

Distinct behavior from symmetric network models

Abstract

We study the transport properties of disordered two-dimensional electron systems with a perfectly conducting channel. We introduce an asymmetric Chalker-Coddington network model and numerically investigate the point-contact conductance. We find that the behavior of the conductance in this model is completely different from that in the symmetric model. Even in the limit of a large distance between the contacts, we find a broad distribution of conductance and a non-trivial power law dependence of the averaged conductance on the system width. Our results are applicable to systems such as zigzag graphene nano-ribbons where the numbers of left-going and right-going channels are different.