Edge State Transport in Separately Contacted Double-Layer Quantum Hall Systems

TL;DR

This paper presents a theoretical analysis of edge state transport in double-layer quantum Hall systems with separate contacts, explaining experimental observations of near-quantized Hall resistance and longitudinal resistance.

Contribution

It develops a theory for edge transport in double-layer quantum Hall systems near tunneling resonance, including predictions for various contact configurations.

Findings

Quantized Hall resistance with zero longitudinal resistance in certain limits

Second-order correction to Hall resistance in weak coupling

First-order longitudinal resistance in weak coupling

Abstract

We develop a theory of edge state transport in separately contacted double-layer quantum Hall systems which are tuned close to the resonance condition for tunneling between the layers. When applied to the case where contact is made to only one layer, the theory gives a quantized Hall resistance and zero longitudinal resistance in both weak and strong inter-layer coupling limits. For weak coupling, the leading correction to the Hall resistance occurs at second order, while the longitudinal resistance appears at first order. Recent experiments which show almost quantized Hall resistance and a substantial longitudinal resistance are explained and predictions are made for other contact configurations.