Decoherence of nuclear spins due to direct dipole-dipole interactions probed by resistively detected nuclear magnetic resonance

TL;DR

This study investigates how direct dipole-dipole interactions cause decoherence of nuclear spins in GaAs quantum wells, using resistively detected NMR to measure decoherence times and effects of magnetic field orientation.

Contribution

It provides the first detailed analysis of dipole-dipole interactions as a decoherence source in GaAs nuclear spins using resistively detected NMR techniques.

Findings

Dipole-dipole interactions significantly contribute to nuclear spin decoherence.

Tilted magnetic fields enhance decoherence by modifying dipole interactions.

Results align with numerical models of dipole-dipole interactions.

Abstract

We study decoherence of nuclear spins in a GaAs quantum well structure using resistively detected nuclear magnetic resonance. The transverse decoherence time T2 of 75As nuclei is estimated from Rabi-type coherent oscillations as well as by using spin-echo techniques. By analyzing T2 obtained by decoupling techniques, we extract the role of dipole-dipole interactions as sources of decoherence in GaAs. Under the condition that the device is tilted in an external magnetic field, we exhibit enhanced decoherence induced by the change in strength of the direct dipole-dipole interactions between first nearest-neighbor nuclei. The results agree well with simple numerical calculations.