Mesoscopic fluctuations of the ground state spin of a small metal particle

TL;DR

This paper investigates how the ground state spin of small metallic particles varies statistically, revealing that even weak interactions can lead to nonzero spins, with implications for experimental observations.

Contribution

It introduces a random-matrix toy model combined with Hartree Fock approximation to analyze ground state spin distributions in small metallic grains, highlighting effects below the Stoner criterion.

Findings

Finite ground state spins occur with notable probability at weak interactions.

The model predicts nonzero spins even below the Stoner threshold.

Discussion of potential experimental relevance.

Abstract

We study the statistical distribution of the ground state spin for an ensemble of small metallic grains, using a random-matrix toy model. Using the Hartree Fock approximation, we find that already for interaction strengths well below the Stoner criterion there is an appreciable probability that the ground state has a finite, nonzero spin. Possible relations to experiments are discussed.