Mechanisms for Spin-Supersolidity in S=1/2 Spin-Dimer Antiferromagnets

TL;DR

This paper derives effective models for S=1/2 spin-dimer antiferromagnets exhibiting supersolid phases under magnetic fields, revealing a 'leapfrog mechanism' that explains supersolidity.

Contribution

It introduces a novel effective Hamiltonian approach and uncovers the 'leapfrog mechanism' as the key to understanding spin-supersolidity in these systems.

Findings

Effective hard-core bosonic Hamiltonians derived

Identification of the 'leapfrog mechanism' for supersolidity

Confirmation of supersolid phases via simulations

Abstract

Using perturbative expansions and the contractor renormalization (CORE) algorithm, we obtain effective hard-core bosonic Hamiltonians describing the low-energy physics of $S=1/2$ spin-dimer antiferromagnets known to display supersolid phases under an applied magnetic field. The resulting effective models are investigated by means of mean-field analysis and quantum Monte Carlo simulations. A "leapfrog mechanism", through means of which extra singlets delocalize in a checkerboard-solid environment via correlated hoppings, is unveiled that accounts for the supersolid behavior.