Vortices in Schwinger-Boson Mean-Field Theory of Two-Dimensional Quantum Antiferromagnets

TL;DR

This paper investigates vortex excitations in two-dimensional quantum antiferromagnets using Schwinger-boson mean-field theory, revealing their stability, topological nature, and statistical properties, with implications for high-temperature superconductor theories.

Contribution

It introduces a continuum description of vortices in quantum antiferromagnets, classifies their types, and discusses their quantum statistics and potential relevance to RVB theories.

Findings

Vortices are stable topological excitations in the disordered state.

Two types of vortices are identified: bosonic zero-angular-momentum and fermionic or bosonic with angular momentum S.

Vortices have implications for understanding high-Tc superconductor models.

Abstract

In this paper we study the properties of vortices in two dimensional quantum antiferromagnets with spin magnitude S on a square lattice within the framework of Schwinger-boson mean field theory. Based on a continuum description, we show that vortices are stable topological excitations in the disordered state of quantum antiferromagnets. Furthermore, we argue that vortices can be divided into two kinds: the first kind always carries zero angular momentum and are bosons, whereas the second kind carries angular momentum S under favourable conditions and are fermions if S is half-integer. A plausible consequence of our results relating to RVB theories of High-Tc superconductors is pointed out.