Metamagnetism in the 2D Hubbard Model with easy axis

TL;DR

This paper demonstrates that the 2D Hubbard model with an easy axis exhibits metamagnetic behavior under an external magnetic field, showing a transition from antiferromagnetic to paramagnetic phases with specific magnetization characteristics.

Contribution

It provides the first detailed quantum Monte Carlo analysis of metamagnetism in the 2D Hubbard model with an easy axis under external magnetic fields.

Findings

Metamagnetic behavior observed with external field

Smooth transition from antiferromagnetic to paramagnetic phase

Critical field B_c marks the onset of uniform magnetization

Abstract

Although the Hubbard model is widely investigated, there are surprisingly few attempts to study the behavior of such a model in an external magnetic field. Using the Projector Quantum Monte Carlo technique, we show that the Hubbard model with an easy axis exhibits metamagnetic behavior if an external field is turned on. For the case of intermediate correlations strength $U$, we observe a smooth transition from an antiferromagnetic regime to a paramagnetic phase. While the staggered magnetization will decrease linearly up to a critical field $B_c$, uniform magnetization develops only for fields higher than $B_c$.