Observation of reentrant quantum Hall states in the lowest Landau level

TL;DR

This study reports the observation of reentrant integer quantum Hall states in the lowest Landau level of high-quality GaAs quantum wells, revealing complex phase competition and density-dependent phenomena.

Contribution

It provides the first experimental evidence of reentrant quantum Hall states near specific filling factors in the lowest Landau level, highlighting the role of electron density and well width.

Findings

Reentrant $ u=1$ quantum Hall states observed near $ u=4/5$ and 6/5.

Reentrant states become more prominent with increased density and well width.

Disappearance and reemergence of $ u=4/5$ fractional quantum Hall effect with density.

Abstract

Measurements in very low disorder two-dimensional electrons confined to relatively wide GaAs quantum well samples with tunable density reveal reentrant $\nu=1$ integer quantum Hall states in the lowest Landau level near filling factors $\nu=4/5$ and 6/5. These states are not seen at low densities and become more prominent with increasing density and in wider wells. Our data suggest a close competition between different types of Wigner crystal states near these fillings. We also observe an intriguing disappearance and reemergence of the $\nu=4/5$ fractional quantum Hall effect with increasing density.