Spin flop in one-dimensional quantum antiferromagnets

TL;DR

This paper investigates the spin flop transition in one-dimensional quantum antiferromagnets with Ising-like anisotropy, revealing different transition types and phases depending on spin magnitude and anisotropy strength.

Contribution

It provides a finite-cluster analysis of the spin flop transition, identifying first- and second-order transitions and incommensurate phases for various spin values and anisotropy levels.

Findings

First-order metamagnetic transition for S≥3/2 with small negative D

Presence of two second-order transitions and an incommensurate phase for intermediate D

Relevance to experimental observations in CsNiCl3

Abstract

The field-induced transition corresponding to the spin flop in the quantum antiferromagnetic chains in the presence of the Ising-like single-ion anisotropy D (<0) is studied by the finite-cluster analysis. It is found that for $S\geq {3\over 2}$ a first-order metamagnetic transition occurs even in one dimension for small negative D except for the Haldane phase, while there exist two second-order transitions and an incommensurate phase appears between them for intermediate D, as already found for S=1. We also discuss on some experiments of CsNiCl$_3$ related with the present work.