The Two-Dimensional S=1 Quantum Heisenberg Antiferromagnet at Finite Temperatures

TL;DR

This study uses quantum Monte Carlo simulations to analyze the temperature-dependent magnetic properties of a 2D spin-1 quantum Heisenberg antiferromagnet, revealing deviations from theoretical predictions at experimentally relevant temperatures.

Contribution

It provides the first comprehensive quantum Monte Carlo analysis of the finite-temperature properties of the 2D spin-1 Heisenberg antiferromagnet, aligning well with experimental data.

Findings

Asymptotic low-temperature behavior is not valid at relevant temperatures.

QMC results agree with experimental measurements of La2NiO4.

The study highlights the importance of finite-temperature effects in 2D quantum antiferromagnets.

Abstract

The temperature dependence of the correlation length, susceptibilities and the magnetic structure factor of the two-dimensional spin-1 square lattice quantum Heisenberg antiferromagnet are computed by the quantum Monte Carlo loop algorithm (QMC). In the experimentally relevant temperature regime the theoretically predicted asymptotic low temperature behavior is found to be not valid. The QMC results however, agree reasonably well with the experimental measurements of La2NiO4 even without considering anisotropies in the exchange interactions.