Field induced transition of the S=1 antiferromagnetic chain with anisotropy

TL;DR

This paper investigates the magnetic phase transitions in an S=1 antiferromagnetic chain with anisotropy, revealing a second-order transition between gapless phases and presenting phase diagrams that suggest re-entrant behavior.

Contribution

It provides a detailed numerical analysis of phase transitions in the S=1 chain with anisotropy, identifying a second-order transition and mapping phase diagrams.

Findings

Second-order phase transition between gapless phases.

Identification of a re-entrant transition in phase diagrams.

Phase diagrams in m-D and H-D planes showing complex behavior.

Abstract

The ground state magnetization process of the S=1 antiferromagnetic chain with the easy-axis single-ion anisotropy described by negative $D$ is investigated. It is numerically found that a phase transition between two different gapless phases occurs at an intermediate magnetic field between the starting and saturation points of the magnetization for $-1.49<D<-0.35$. The transition is similar to the spin flopping, but it is second-order and not accompanied with any significant anomalous behaviors in the magnetization curve. We also present the phase diagrams in the m-D and H-D planes which reveal a possible re-entrant transition.