Optically induced nuclear spin polarization in a single GaAs/AlGaAs quantum well probed by a resistance detection method in the fractional quantum Hall regime

TL;DR

This study investigates optically induced nuclear spin polarization in a single GaAs/AlGaAs quantum well within the fractional quantum Hall regime, using resistive detection to analyze nuclear spin dynamics and the effects of electron interactions.

Contribution

It introduces a high-sensitivity resistive detection method to probe nuclear spins in a quantum well and explores the influence of phonon emission and electron-electron interactions on optical nuclear polarization.

Findings

Optical nuclear polarization spectra show electron-spin-resolved Landau level transitions.

Phonon emission influences the efficiency of optical nuclear spin polarization.

Electron-electron interactions significantly affect nuclear spin polarization processes.

Abstract

We study the optically pumped nuclear spin polarization in a single GaAs/AlGaAs quantum well in the quantum Hall system. We apply resistive detection via the contact hyperfine interaction, which provides high sensitivity and selectivity, to probe a small amount of polarized nuclear spins in a single well. The properties of the optical nuclear spin polarization are clearly observed. We theoretically discuss the nuclear spin dynamics accompanied with doped electrons to analyze the experimental data. The optical nuclear polarization spectra exhibit electron-spin-resolved lowest Landau level interband transitions. We find that the phonon emission process, which normally assists the optical pumping process, influences the optical nuclear spin polarization. We also discuss that the electron-electron interaction can play an important role in the optical nuclear spin polarization.