Antiferromagnetism in the 2D Hubbard model: phase transition and local quantities

TL;DR

This paper investigates the antiferromagnetic phase in the 2D Hubbard model at finite temperatures, analyzing phase transitions and local quantities using a self-consistent composite operator method.

Contribution

It introduces a self-consistent approach to study antiferromagnetism in the 2D Hubbard model, including phase transition details and local property calculations.

Findings

Critical Coulomb repulsion varies with t' near half-filling.

Magnetization depends on temperature and Coulomb interaction.

Internal energy per site shows characteristic behavior near phase transition.

Abstract

We present a first study of the antiferromagnetic state in the 2D t-t'-U model at finite temperatures by the composite operator method, providing simultaneously a fully self-consistent treatment of the paramagnetic and the AF phase. Near half-filling the critical value of the Coulomb repulsion as a function of t' and the temperature dependence of the magnetization and of the internal energy per site have been studied.