Effects of randomness on the antiferromagnetic spin-1 chain

TL;DR

This paper studies how weak randomness affects the antiferromagnetic spin-1 chain, revealing phase destruction and instabilities using bosonization and renormalization group methods.

Contribution

It introduces a detailed theoretical analysis of disorder effects on the spin-1 chain, including predictions for various random field configurations.

Findings

Destruction of antiferromagnetic order due to randomness

Different instability mechanisms compared to spin ladders

Predictions for effects of random magnetic fields

Abstract

We investigate the effect of weak randomness on the antiferromagnetic anisotropic spin-1 chain. We use Abelian bosonization to construct the low-energy effective theory. A renormalization group calculation up to second order in the strength of the disorder is performed on this effective theory. We observe in this framework the destruction of the antiferromagnetic ordered phase `a la Imry-Ma. We predict the effects of a random magnetic field along z axis, a random field in the XY plane as well as random exchange with and without XY symmetry. Instabilities of massless phases appear in general by mechanisms different from the case of the 2-leg spin ladder.