Antiferromagnetic Correlation under the External Magnetic Field in the Hubbard Model

TL;DR

This paper explores how external magnetic fields influence antiferromagnetic correlations in the Hubbard model, revealing phase diagrams, magnetization behaviors, and reentrant phenomena through a generalized theoretical approach.

Contribution

It introduces a generalized Harper's equation to analyze temperature and doping effects on antiferromagnetism under magnetic fields, providing new insights into phase behavior.

Findings

Maximum staggered magnetization occurs away from half filling.

Reentrant behavior of magnetization observed under magnetic field.

Finite temperature plateau of magnetization near half filling.

Abstract

By deriving a generalized Harper's equation, we investigate the effects of temperature $T$ and hole doping $\d$ on antiferromagnetically correlated electrons under the influence of an applied magnetic field. We obtain a phase diagram in a $T$-$\d$ plane for staggered magnetization under the external field. We find that away from half filling the maximum values of staggered magnetization occur with rapid convergence to a finite temperature constant near half filling. We discover the reentrant behavior of the staggered magnetization in the presence of the magnetic field.