Probing Landau quantisation with the presence of insulator-quantum Hall transition in a GaAs two-dimensional electron system

TL;DR

This study investigates Landau quantisation and insulator-quantum Hall transition in a GaAs 2DES, revealing that the transition does not always indicate strong localization, with magneto-transport measurements highlighting nuanced electronic behaviors.

Contribution

It demonstrates that the insulator-quantum Hall transition does not necessarily coincide with strong localization, providing new insights into Landau quantisation in 2DES.

Findings

Magnetoresistivity oscillations linked to Landau quantisation observed near I-QH transition

Different mobilities are derived from oscillations and transition point

I-QH transition does not always indicate the onset of strong localization

Abstract

Magneto-transport measurements are performed on the two-dimensional electron system (2DES) in an AlGaAs/GaAs heterostructure. By increasing the magnetic field perpendicular to the 2DES, magnetoresistivity oscillations due to Landau quantisation can be identified just near the direct insulator-quantum Hall (I-QH) transition. However, different mobilities are obtained from the oscillations and transition point. Our study shows that the direct I-QH transition does not always correspond to the onset of strong localisation.