Metamagnetism of antiferromagnetic XXZ quantum spin chains

TL;DR

This paper investigates the magnetization behavior of one-dimensional antiferromagnetic XXZ spin chains, revealing a first-order spin flop transition with a magnetization jump for spins S≥1, and a second-order transition for S=1/2 due to quantum fluctuations.

Contribution

It provides the first exact diagonalization evidence of the order of the metamagnetic transition in antiferromagnetic XXZ chains, highlighting the special case of S=1/2.

Findings

First-order spin flop transition with magnetization jump for S≥1

Second-order transition for S=1/2 due to quantum fluctuations

Evidence obtained through exact diagonalization

Abstract

The magnetization process of the one-dimensional antiferromagnetic Heisenberg model with the Ising-like anisotropic exchange interaction is studied by the exact diagonalization technique. It results in the evidence of the first-order spin flop transition with a finite magnetization jump in the N\'eel ordered phase for $S\geq 1$. It implies that the S=1/2 chain is an exceptional case where the metamagnetic transition becomes second-order due to large quantum fluctuations.