CaMn$_{2}$Sb$_{2}:$ a fully frustrated classical magnetic system

TL;DR

CaMn₂Sb₂ is a highly frustrated magnetic system near a critical point, leading to degenerate magnetic phases and potentially explaining its unusual physical properties and intermediate temperature phase.

Contribution

This study identifies CaMn₂Sb₂ as a classical magnetic system close to a critical point with degenerate phases, providing insight into its complex magnetic behavior.

Findings

CaMn₂Sb₂ is near a mean-field critical point for the Heisenberg model.

Three magnetic phases become degenerate at this critical point.

The compound's unusual properties may stem from this proximity.

Abstract

We show by means of density functional calculations that CaMn$_{2}$Sb$_{2}$ is very close to a mean-field critical point known for the classical Heisenberg model on the honeycomb lattice. Three entirely different long range ordered magnetic phases become degenerate at this point: the Neel phase and two different spiral phases. We speculate that the unusual physical properties of this compound, observed in recent experiments, in particular the enigmatic intermediate temperature phase, are due to this proximity.