Vertical Confinement and Evolution of Reentrant Insulating Transition in the Fractional Quantum Hall Regime

TL;DR

This study investigates how vertical confinement in a narrow quantum well influences the reentrant insulating phases in the fractional quantum Hall regime, revealing a shift in transition points due to confinement effects.

Contribution

It demonstrates that confinement significantly alters the reentrant insulating transition, shifting it from ν=1/5 to ν=1/3, highlighting the role of quantum well width in quantum Hall phenomena.

Findings

Transition shifts from ν=1/5 to ν=1/3 in narrow wells

Disorder effects are minimal due to high quantum lifetime

Confinement is identified as the key factor affecting the transition

Abstract

We have observed an anomalous shift of the high field reentrant insulating phases in a two-dimensional electron system (2DES) tightly confined within a narrow GaAs/AlGaAs quantum well. Instead of the well-known transitions into the high field insulating states centered around $\nu = 1/5$, the 2DES confined within an 80\AA-wide quantum well exhibits the transition at $\nu = 1/3$. Comparably large quantum lifetime of the 2DES in narrow well discounts the effect of disorder and points to confinement as the primary driving force behind the evolution of the reentrant transition.