The effect of inter-Landau-band mixing on extended states in quantum Hall system

TL;DR

This paper investigates how inter-Landau-band mixing influences electron localization in quantum Hall systems, revealing that such mixing can create extended states and a metallic phase, supported by numerical simulations and experimental data analysis.

Contribution

It introduces a new phase diagram with a metallic phase caused by inter-Landau-band mixing, supported by numerical modeling and reanalysis of experimental data.

Findings

Inter-Landau-band mixing can delocalize localized states.

Extended states form bands due to mixing, leading to a metallic phase.

Experimental data is consistent with the proposed phase diagram.

Abstract

The effect of inter-Landau-band mixing on electron localization in an integer quantum Hall system is studied. We find that mixing of localized states with {\it opposite chirality} tends to delocalize the states. This delocalization effect survives the quantum treatment. Extended states form bands because of this mixing, as we show through a numerical calculation on a two-channel network model. Based on this result, we propose a new phase diagram with a narrow {\it metallic} phase that separates any neighboring QH phases from each other and also separates each of them from the insulating phase. We reanalyzed the data from recent non-scaling experiments, and show that they are {\it consistent} with our theory.