Probing onset of strong localization and electron-electron interactions with the presence of direct insulator-quantum Hall transition

TL;DR

This study investigates the transition from insulator to quantum Hall states in a disordered 2D electron system, highlighting the role of electron-electron interactions and clarifying the nature of strong localization onset.

Contribution

It demonstrates that the insulator-quantum Hall transition does not coincide with the onset of strong localization and emphasizes the significance of electron-electron interactions in this transition.

Findings

Strong localization features appear after the transition.

The transition is influenced by electron-electron interactions.

The insulator-quantum Hall transition is not the onset of strong localization.

Abstract

We have performed low-temperature transport measurements on a disordered two-dimensional electron system (2DES). Features of the strong localization leading to the quantum Hall effect are observed after the 2DES undergoes a direct insulator-quantum Hall transition with increasing the perpendicular magnetic field. However, such a transition does not correspond to the onset of strong localization. The temperature dependences of the Hall resistivity and Hall conductivity reveal the importance of the electron-electron interaction effects to the observed transition in our study.