Finite-size spin-wave theory of the triangular Heisenberg model

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.