Confinement and deconfinement of spinons in a frustrated spin-1/2 Heisenberg model

TL;DR

This paper analyzes the phase diagram of a frustrated spin-1/2 Heisenberg model, focusing on the confinement and deconfinement of spinons within different magnetic and valence bond phases.

Contribution

It clarifies the location of deconfined spinons in the phase diagram, particularly within the valence bond crystal state, refining previous theoretical predictions.

Findings

Deconfined spinons are located in the middle of the VBC state.

The phase diagram includes $(\pi,0)$ and $(\pi,\pi)$ antiferromagnetic phases.

The dimerization order parameter changes sign at the deconfinement point.

Abstract

In this publication I discuss the phase diagram of a frustrated spin-1/2 Heisenberg model suggested in A. A. Nersesyan and A. M. Tsvelik, Phys. Rev. B{\bf 67}, 024422 (2003). The phase diagram contains $(\pi,0)$ and $(\pi,\pi)$ antiferromagnetic phases separated by the Valence Bond Crystal (VBC) state. I argue that the point of the phase diagram with deconfined spinons, predicted in the aforementioned work, is situated in the middle of VBC state, at the point where the dimerization order parameter changes sign.