Spin transition in the fractional quantum Hall regime: Effect of extent of the wave function

TL;DR

This study investigates how the extent of the electron wave function influences the spin transition magnetic field in the fractional quantum Hall regime, revealing a significant decrease in B* with increased wave function extent.

Contribution

It provides experimental and theoretical analysis showing the effect of wave function extent on spin transition fields without requiring fitting parameters.

Findings

B* decreases as wave function extent increases

Coulomb energy and g factor changes contribute equally to B* shift

Theoretical model matches experimental data without fitting parameters

Abstract

Using a magnetocapacitance technique, we determine the magnetic field of the spin transition, B*, at filling factor nu=2/3 in the 2D electron system in GaAs/AlGaAs heterojunctions. The field B* is found to decrease appreciably as the wave function extent controlled by back gate voltage is increased. Our calculations show that the contributions to the shift of B* from the change of the Coulomb energy and the g factor change due to nonparabolicity are approximately the same. The observed relative shift of B* is described with no fitting parameters.