Spin Dependence of Correlations in Two-Dimensional Quantum Heisenberg Antiferromagnets

TL;DR

This study investigates how spin magnitude affects correlations in two-dimensional quantum Heisenberg antiferromagnets, revealing deviations from classical predictions and proposing a crossover scaling scenario based on series expansion data.

Contribution

It provides the first detailed series expansion analysis of spin-S square-lattice Heisenberg antiferromagnets, highlighting deviations from classical scaling and proposing a new crossover scenario.

Findings

Correlation length for S>1/2 deviates from classical scaling predictions.

Series expansion data agrees with neutron scattering measurements.

Proposes a scaling crossover scenario to explain trends with S.

Abstract

We present a series expansion study of spin-S square-lattice Heisenberg antiferromagnets. The numerical data are in excellent agreement with recent neutron scattering measurements. Our key result is that the correlation length for S>1/2 strongly deviates from the exact T->0 (renormalized classical, or RC) scaling prediction for all experimentally and numerically accessible temperatures. We note basic trends with S of the experimental and series expansion correlation length data and propose a scaling crossover scenario to explain them.