Ordered Phases of the Anisotropic Kagome Lattice Antiferromagnet in a Field

TL;DR

This paper investigates the phase transitions and magnetic orderings in an anisotropic kagome lattice antiferromagnet under a magnetic field, revealing a transition from ferrimagnetic to XY order and discussing magnetization plateaux.

Contribution

It introduces a symmetry-based and perturbative approach to analyze the anisotropic kagome lattice antiferromagnet in a field, highlighting a quantum phase transition and magnetization phenomena.

Findings

Quantum phase transition from ferrimagnetic to XY order

Appearance of magnetization plateaux in the ferrimagnetic phase

System behavior modeled by weakly interacting spin chains

Abstract

The antiferromagnetic Heisenberg model on an anisotropic kagome lattice may be a good minimal model for real magnetic systems as well as a limit from which the isotropic case can be better understood. We therefore study the nearest-neighbor Heisenberg antiferromagnet on an anisotropic kagome lattice in a magnetic field. Such a system should be well described by weakly interacting spin chains, and we motivate a general form for the interaction by symmetry considerations and by perturbatively projecting out the inter-chain spins. In the spin 1/2 case, we find that the system exhibits a quantum phase transition from a ferrimagnetic ordered state to an XY ordered state as the field is increased. Finally, we discuss the appearance of magnetization plateaux in the ferrimagnetic phase.