$\nu=1/2$ Fractional Quantum Hall Effect in Tilted Magnetic Fields

TL;DR

This study investigates how tilting the magnetic field affects the ground state at filling factor ν=1/2 in two-dimensional electrons, revealing a transition from a compressible state to a fractional quantum Hall state and then to an insulating phase.

Contribution

It demonstrates the evolution of the ν=1/2 ground state under tilted magnetic fields, highlighting the role of charge distribution changes in quantum Hall phenomena.

Findings

Emergence of a ν=1/2 fractional quantum Hall state at intermediate tilt angles.

Transition to an insulating phase at high tilt angles.

Charge distribution becomes bilayer-like with increased tilt.

Abstract

Magnetotransport measurements on two-dimensional electrons confined to wide GaAs quantum wells reveal a remarkable evolution of the ground state at filling factor $\nu=1/2$ as we tilt the sample in the magnetic field. Starting with a compressible state at zero tilt angle, a strong $\nu=1/2$ fractional quantum Hall state appears at intermediate angles. At higher angles an insulating phase surrounds this state and eventually engulfs it at the highest angles. This evolution occurs because the parallel component of the field renders the charge distribution increasingly bilayer-like.