Approaching Kasteleyn transition in frustrated quantum Heisenberg antiferromagnets

TL;DR

This paper explores the relevance of the Kasteleyn transition, known from classical models, to frustrated 2D quantum magnets, demonstrating its occurrence in a specific quantum spin model and discussing broader implications.

Contribution

It introduces a quantum analog of the Kasteleyn transition in frustrated quantum magnets and maps a specific phase of the Heisenberg model onto a dimer covering problem.

Findings

Identification of a quantum Kasteleyn transition in a spin-1/2 Heisenberg model.

Mapping of a quantum phase onto an effective dimer model with tunable parameters.

Prediction of an arbitrarily sharp crossover resembling the Kasteleyn transition.

Abstract

We show that the Kasteleyn transition, the abrupt proliferation of infinite strings of defects in classical dimer and related models, can also be relevant for frustrated 2d quantum magnets. This is explicitly demonstrated in a phase of the spin-1/2 Heisenberg diamond-decorated honeycomb lattice where a family of exact eigenstates built as products of dimer and plaquette singlets can be mapped onto the dimer coverings of the honeycomb lattice. The low-temperature properties of this phase are accurately described by an effective dimer model with anisotropic activities and a small, tunable density of monomers, leading to an arbitrarily sharp crossover version of the Kasteleyn transition. The generalization to other geometries and the possibility to realize this model in organo-metallic compounds are briefly discussed.