Dynamical nuclear polarization and nuclear magnetic fields in semiconductor nanostructures

TL;DR

This paper explores how dynamic nuclear polarization in semiconductor nanostructures can generate significant, tunable nuclear magnetic fields, impacting optical nuclear magnetic resonance techniques.

Contribution

It derives the spatial and temporal behavior of nuclear polarization and magnetic fields, demonstrating high polarization levels and tunability in GaAs/AlGaAs quantum wells.

Findings

Nuclear spin polarization can reach 80% in GaAs/AlGaAs quantum wells.

Induced magnetic fields can approach a few gauss and are tunable with electric fields.

Nuclear resonance shifts of the order of kHz are achievable with full electronic spin polarization.

Abstract

We investigate the dynamic nuclear polarization from the hyperfine interaction between nonequilibrium electronic spins and nuclear spins coupled to them in semiconductor nanostructures. We derive the time and position dependence of the induced nuclear spin polarization and dipolar magnetic fields. In GaAs/AlGaAs parabolic quantum wells the nuclear spin polarization can be as high as 80% and the induced nuclear magnetic fields can approach a few gauss with an associated nuclear resonance shift of the order of kHz when the electronic system is 100% spin polarized. These fields and shifts can be tuned using small electric fields. We discuss the implications of such control for optical nuclear magnetic resonance experiments in low-dimensional semiconductor nanostructures.