Exact low-temperature behavior of kagome antiferromagnet at high fields

TL;DR

This paper provides an exact solution for the low-temperature behavior of a kagome antiferromagnet near saturation by mapping it to a solvable hard-hexagon model, enabling precise thermodynamic predictions and critical behavior analysis.

Contribution

It introduces an exact mapping of the kagome antiferromagnet's low-energy states to a hard-hexagon model, offering new quantitative insights.

Findings

Quantitative description of magnetothermodynamics near saturation

Prediction of critical behavior for magnon crystal transition

Exact solutions with exponentially small corrections

Abstract

Low-energy degrees of freedom of a spin-1/2 kagome antiferromagnet in the vicinity of the saturation field are mapped to a hard-hexagon model on a triangular lattice. The latter model is exactly solvable. The presented mapping allows to obtain quantitative description of the magnetothermodynamics of a quantum kagome antiferromagnet up to exponentially small corrections as well as predict the critical behavior for the transition into a magnon crystal state. Analogous mapping is presented for the sawtooth chain, which is mapped onto a model of classical hard dimers on a chain.