Effects of Quantum-Well Inversion Asymmetry on Electron-Nuclear Spin Coupling in the Fractional Quantum Hall Regime

TL;DR

This study investigates how inversion asymmetry in a GaAs/AlGaAs quantum well influences electron-nuclear spin interactions in the fractional quantum Hall regime, revealing that asymmetry modulates spin polarization and relaxation via Rashba spin-orbit effects.

Contribution

It demonstrates the impact of quantum well inversion asymmetry on electron-nuclear spin coupling, highlighting the role of Rashba spin-orbit interaction in the fractional quantum Hall regime.

Findings

Increased asymmetry suppresses nuclear spin polarization at nu=2/3.

Asymmetry enhances nuclear spin relaxation at general filling factors.

Spin state mixing due to Rashba interaction affects spin coupling.

Abstract

We examine effects of inversion asymmetry of a GaAs/Al0.3Ga0.7As quantum well (QW) on electron-nuclear spin coupling in the fractional quantum Hall (QH) regime. Increasing the QW potential asymmetry at a fixed Landau-level filling factor (nu) with gate voltages suppresses the current-induced nuclear spin polarization in the nu = 2/3 Ising QH ferromagnet, while it significantly enhances the nuclear spin relaxation at general nu. These findings suggest that mixing of different spin states due to the Rashba spin-orbit interaction strongly affects the electron-nuclear spin coupling.