Phase separation in the Hubbard model

TL;DR

This study investigates phase separation in the Hubbard model using dynamical cluster approximation, revealing its occurrence in paramagnetic solutions at finite temperature with positive next-nearest neighbor hopping, driven by doped regions with strong antiferromagnetic correlations.

Contribution

It demonstrates the presence of phase separation in the Hubbard model under specific conditions, highlighting the role of doped regions and magnetic correlations.

Findings

Phase separation occurs for fillings less than one at finite temperature.

It involves a mixture of metallic and Mott insulating phases.

Doped regions with strong antiferromagnetic correlations drive phase separation.

Abstract

Phase separation in the Hubbard model is investigated with the dynamical cluster approximation. We find that it is present in the paramagnetic solution for values of filling smaller than one and at finite temperature when a positive next-nearest neighbor hopping is considered. The phase separated region is characterized by a mixture of a strongly correlated metallic and Mott insulating phases. Our results indicate that phase separation is driven by the formation of doped regions with strong antiferromagnetic correlations and low kinetic energy