Lattice gas description of pyrochlore and checkerboard antiferromagnets in a strong magnetic field

TL;DR

This paper maps quantum antiferromagnets on pyrochlore and checkerboard lattices under strong magnetic fields to hard-core lattice gases, analyzing phase transitions and magnon crystal states through simulations and exact calculations.

Contribution

It introduces a lattice gas model for pyrochlore and checkerboard antiferromagnets in high magnetic fields, providing new insights into their phase behavior and ground states.

Findings

Transition point and critical exponents for the checkerboard lattice gas were numerically determined.

The exact structure of the magnon crystal state in pyrochlore antiferromagnets was identified.

The models accurately describe the magnetic properties of the studied antiferromagnets.

Abstract

Quantum Heisenberg antiferromagnets on pyrochlore and checkerboard lattices in a strong external magnetic field are mapped onto hard-core lattice gases with an extended exclusion region. The effective models are studied by the exchange Monte Carlo simulations and by the transfer matrix method. The transition point and the critical exponents are obtained numerically for a square-lattice gas of particles with the second-neighbor exclusion, which describes a checkerboard antiferromagnet. The exact structure of the magnon crystal state is determined for a pyrochlore antiferromagnet.