Thermodynamic properties of the two-dimensional S=1/2 Heisenberg antiferromagnet coupled to bond phonons

TL;DR

This study uses quantum Monte Carlo simulations to analyze how bond phonons influence the thermodynamic properties and magnetic order of the two-dimensional S=1/2 Heisenberg antiferromagnet.

Contribution

It provides detailed insights into the temperature dependence of thermodynamic quantities and the persistence of long-range order under different spin-phonon couplings.

Findings

Long-range Neel order persists at zero temperature in both weak and strong coupling regimes.

Thermodynamic properties vary significantly with coupling strength and temperature.

Finite size scaling confirms the stability of antiferromagnetic order.

Abstract

By applying a quantum Monte Carlo procedure based on the loop algorithm we investigate thermodynamic properties of the two-dimensional antiferromagnetic S=1/2 Heisenberg model coupled to Einstein phonons on the bonds. The temperature dependence of the magnetic susceptibility, mean phonon occupation numbers and the specific heat are discussed in detail. We study the spin correlation function both in the regime of weak and strong spin phonon coupling (coupling constants g=0.1, w=8J and g=2, w=2J, respectively). A finite size scaling analysis of the correlation length indicates that in both cases long range Neel order is established in the ground state.