Effects of edge disorder in nano-scale antiferromagnetic clusters

TL;DR

This study investigates how edge disorder in nano-scale antiferromagnetic clusters affects local magnetic susceptibilities and NMR line widths, suggesting experimental detection of edge effects in magnetic structures.

Contribution

It provides a detailed analysis of edge disorder effects on magnetic susceptibility distributions in 2D antiferromagnetic clusters, highlighting potential experimental signatures.

Findings

Line widths broader than average shift are expected due to edge disorder.

Edge effects depend on cluster size and edge nature.

NMR experiments can reveal magnetic edge structures.

Abstract

We study the distribution of local magnetic susceptibilities in the two-dimensional antiferromagnetic S=1/2 Heisenberg model on various random clusters, in order to determine whether effects of edge disorder could be detected in NMR experiments (through the line shape, as given by the distribution of local Knight shifts). Although the effects depend strongly on the nature of the edge and the cluster size, our results indicate that line widths broader than the average shift should be expected even in clusters as large as $\approx 1000$ lattice spacing in diameter. Experimental investigations of the NMR line width should give insights into the magnetic structure of the edges.