Measurements of strongly-anisotropic g-factors for spins in single quantum states

TL;DR

This study measures the angular dependence of Zeeman splitting in copper nanoparticle energy states, revealing highly anisotropic g-factors that vary between levels and align with theoretical predictions.

Contribution

It provides the first detailed measurement of anisotropic g-factors for individual quantum states in nanoparticles, confirming theoretical models.

Findings

g-factors vary by up to a factor of five with angle

Angular dependence fits ellipsoid models

Variations match random-matrix theory predictions

Abstract

We have measured the full angular dependence, as a function of the direction of magnetic field, for the Zeeman splitting of individual energy states in copper nanoparticles. The g-factors for spin splitting are highly anisotropic, with angular variations as large as a factor of five. The angular dependence fits well to ellipsoids. Both the principal-axis directions and g-factor magnitudes vary between different energy levels within one nanoparticle. The variations agree quantitatively with random-matrix theory predictions which incorporate spin-orbit coupling.