Order of Two-Dimensional Isotropic Dipolar Antiferromagnets

TL;DR

This paper investigates whether two-dimensional isotropic dipolar Heisenberg antiferromagnets can exhibit magnetic order, finding that dipolar interactions induce a gap and finite Néel temperature, indicating possible magnetic order in such systems.

Contribution

It demonstrates that dipolar interactions create a gap and enable finite-temperature order in 2D isotropic antiferromagnets, using linear spin-wave theory.

Findings

Dipolar interactions induce a gap in the spin-wave spectrum.

A finite Néel temperature is calculated for a square lattice.

Order can exist in 2D isotropic dipolar antiferromagnets due to dipolar interactions.

Abstract

The question of the existence of order in two-dimensional isotropic dipolar Heisenberg antiferromagnets is studied. It is shown that the dipolar interaction leads to a gap in the spin-wave energy and a nonvanishing order parameter. The resulting finite N\'eel-temperature is calculated for a square lattice by means of linear spin-wave theory.