Maple Leaf Antiferromagnet in a Magnetic Field

TL;DR

This paper investigates the quantum antiferromagnet on the maple leaf lattice under a magnetic field, revealing superfluid-insulator transitions and magnetization plateaux through an effective hardcore boson model derived from strong coupling expansion.

Contribution

It introduces a novel effective hardcore boson model for the maple leaf antiferromagnet in a magnetic field, highlighting the role of many-body interactions and correlated hopping in magnetization plateaux formation.

Findings

Identification of superfluid to insulator transitions at specific magnetizations.

Observation of density wave order dominating intermediate magnetization plateaux.

Conjecture of multi-boson bound states causing plateau formation at lower magnetizations.

Abstract

We analyze the quantum antiferromagnet on the maple leaf lattice in the presence of a magnetic field. Starting from its exact dimer ground state and for a magnetic field strength of the order of the local dimer spin exchange coupling, we perform a strong coupling expansion and extract an effective hardcore boson model. The interplay of effective many-body interactions, suppressed single-particle dynamics, and correlated hopping gives way to an intriguing series of superfluid to insulator transitions which correspond to magnetization plateaux in terms of the maple leaf spin degrees of freedom. While we find plateaux at intermediate magnetization to be dominated by bosonic density wave order, we conjecture plateau formation from multi-boson bound states due to correlated hopping for lower magnetization.