Spin-Reorientation Transition of Field-Induced Magnetic Ordering Phases in the Anisotropic Haldane System

TL;DR

This paper predicts a spin-reorientation transition in the field-induced magnetic phases of an anisotropic S=1 Haldane system, using theoretical models and numerical methods, with implications for understanding high-field magnetic phases.

Contribution

It introduces a novel prediction of spin-reorientation transition in the Haldane system with easy-plane anisotropy, linking it to order parameter variations at zero temperature.

Findings

Prediction of spin-reorientation transition when magnetic field is inclined from easy axis.

Identification of the transition's connection to order parameter changes at zero temperature.

Discussion of implications for recently observed high-field magnetic phases.

Abstract

A possible spin-reorientation transition in field-induced magnetic ordering phases of the S=1 Haldane system with large easy-plane anisotropy is proposed, using an effective Lagrangian formalism as well as the density matrix renormalization group method. Such a spin-reorientation transition is predicted in the case where the applied magnetic field is inclined from the easy axis of the anisotropy. We point out that this transition has a close connection with a variation of the order parameter even at zero temperature, although it is different from a quantum analog of the so-called spin-flop transition proposed for the system having a strong easy axis anisotropy. In connection with a novel phase observed recently in the Haldane system at high fields, we discuss possible implications for the field-induced magnetic ordering.