Geometric Resonance of Composite Fermions near Bilayer Quantum Hall States

TL;DR

This study investigates how composite fermions behave near bilayer quantum Hall states in wide GaAs quantum wells, revealing layer preferences and the influence of magnetic fields on their properties.

Contribution

It provides new insights into the layer-dependent behavior of composite fermions near bilayer quantum Hall states under varying magnetic conditions.

Findings

CFs near ν=1 prefer to stay in separate layers, showing two-component behavior.

CFs near ν=1/2 behave as single-layer-like, indicating single-component behavior.

Geometric resonance features depend on the Landau level filling factor and total electron density.

Abstract

Via the application of parallel magnetic field, we induce a single-layer to bilayer transition in two-dimensional electron systems confined to wide GaAs quantum wells, and study the geometric resonance of composite fermions (CFs) with a periodic density modulation in our samples. The measurements reveal that CFs exist close to bilayer quantum Hall states, formed at Landau level filling factors $\nu=1$ and 1/2. Near $\nu=1$, the geometric resonance features are consistent with half the total electron density in the bilayer system, implying that CFs prefer to stay in separate layers and exhibit a two-component behavior. In contrast, close to $\nu=1/2$, CFs appear single-layer-like (single-component) as their resonance features correspond to the total density.