Weakly frustrated two-dimensional Heisenberg antiferromagnets: thermodynamic properties from a non-perturbative approach

TL;DR

This paper uses a non-perturbative renormalization group approach to analyze thermodynamic properties of frustrated two-dimensional quantum Heisenberg antiferromagnets, providing insights into phase stability and quantum corrections.

Contribution

It applies the quantum hierarchical reference theory to study thermodynamics and ground state properties of frustrated 2D Heisenberg antiferromagnets, offering new non-perturbative insights.

Findings

Finite temperature susceptibility and correlation length are characterized.

Ground state properties like spin stiffness are extrapolated from finite temperature data.

The results suggest potential breakdown of the Neel phase at higher frustration levels.

Abstract

We analyze the thermodynamic properties of the spin-S two-dimensional quantum Heisenberg antiferromagnet on a square lattice with nearest and next-nearest neighbor couplings in the Neel phase (J_2/J_1<0.4) employing the quantum hierarchical reference theory (QHRT), a non-perturbative implementation of the renormalization group method to quantum systems. We investigate the staggered susceptibility, the structure factors and the correlation length at finite temperature and for different values of the frustration ratio. From the finite temperature results, we also extrapolate ground state properties, such as spin stiffness and spontaneous staggered magnetization, providing an estimate of the extent of quantum corrections. The behavior of these quantities as a function of frustration may provide some hint on the breakdown of the Neel phase at zero temperature for larger values of J_2.