Measurement of statistical nuclear spin polarization in a nanoscale GaAs sample

TL;DR

This study demonstrates the measurement of statistical nuclear spin polarization in a nanoscale GaAs sample using magnetic resonance force microscopy, paving the way for nanometer-scale 3D magnetic resonance imaging of III-V materials.

Contribution

It introduces a method to detect statistical nuclear spin polarization in extremely small GaAs samples, advancing nanoscale magnetic resonance techniques.

Findings

Successful NMR detection in <5 x 10^8 spins

Achieved detection volume of (300 nm)^3

Discussed future reduction of detection volume

Abstract

We measure the statistical polarization of quadrupolar nuclear spins in a sub-micrometer (0.6 um^3) particle of GaAs using magnetic resonance force microscopy. The crystalline sample is cut out of a GaAs wafer and attached to a micro-mechanical cantilever force sensor using a focused ion beam technique. Nuclear magnetic resonance is demonstrated on ensembles containing less than 5 x 10^8 nuclear spins and occupying a volume of around (300 nm)^3 in GaAs with reduced volumes possible in future experiments. We discuss how the further reduction of this detection volume will bring the spin ensemble into a regime where random spin fluctuations, rather than Boltzmann polarization, dominate its dynamics. The detection of statistical polarization in GaAs therefore represents an important first step toward 3D magnetic resonance imaging of III-V materials on the nanometer-scale.