Finite size Spin Wave theory of the triangular Heisenberg model

TL;DR

This paper uses finite size spin wave theory to analyze the low-energy excitations of the triangular Heisenberg antiferromagnet, showing good agreement with exact methods and supporting the theory's reliability in frustrated systems.

Contribution

It demonstrates the effectiveness of finite size spin wave calculations in describing low-energy excitations in frustrated quantum magnets.

Findings

Spin wave theory agrees well with exact diagonalization and quantum Monte Carlo results.

The spin susceptibility closely matches the linear spin wave prediction.

Supports the use of spin wave expansion for frustrated antiferromagnets.

Abstract

We present a finite size spin wave calculation on the Heisenberg antiferromagnet on the triangular lattice focusing in particular on the low-energy part of the excitation spectrum. For s=1/2 the good agreement with the exact diagonalization and quantum Monte Carlo results supports the reliability of the spin wave expansion to describe the low-energy spin excitations of the Heisenberg model even in presence of frustration. This indicates that the spin susceptibility of the triangular antiferromagnet is very close to the linear spin wave result.