Morphing of 2D Hole Systems at $\nu=3/2$ in Parallel Magnetic Fields: Compressible, Stripe, and Fractional Quantum Hall Phases

TL;DR

This study explores how 2D hole systems in wide GaAs quantum wells transition between compressible, stripe, and fractional quantum Hall phases at filling factor 3/2 under tilted magnetic fields, revealing complex phase competition.

Contribution

It demonstrates the tunable competition between different many-body phases in 2D hole systems at $ u=3/2$ influenced by charge distribution symmetry and magnetic field tilt.

Findings

Stripe phase appears at large tilt angles with symmetric charge distribution.

Asymmetric charge distribution leads to fractional quantum Hall state at $ u=3/2$.

Phase transitions are driven by Landau level mixing in tilted fields.

Abstract

A transport study of two-dimensional (2D) holes confined to wide GaAs quantum wells provides a glimpse of a subtle competition between different many-body phases at Landau level filling $\nu=3/2$ in tilted magnetic fields. At large tilt angles ($\theta$), an anisotropic, stripe (or nematic) phase replaces the isotropic compressible Fermi sea at $\nu=3/2$ if the quantum well has a symmetric charge distribution. When the charge distribution is made asymmetric, instead of the stripe phase, an even-denominator fractional quantum state appears at $\nu=3/2$ in a range of large $\theta$, and reverts back to a compressible state at even higher $\theta$. We attribute this remarkable evolution to the significant mixing of the excited and ground-state Landau levels of 2D hole systems in tilted fields.