Functional-integral approach to the investigation of the spin-spiral magnetic order and phase separation

TL;DR

This paper uses a functional-integral approach to study magnetic phases and phase separation in a 2D Hubbard model, revealing temperature effects on magnetic order and implications for cuprate materials.

Contribution

It introduces a Hubbard-Stratonovich transformation with a two-field representation to analyze magnetic phases at finite temperature.

Findings

Temperature significantly affects magnetic phases.

Phase separation occurs near half-filling.

Results suggest explanations for magnetic behavior in cuprates.

Abstract

We investigate a two-dimensional single-band Hubbard model with a nearest-neighbor hopping. We treat a commensurate collinear order as well as incommensurate spiral magnetic phases at a finite temperature using a Hubbard-Stratonovich transformation with a two-field representation and solve this problem in a static approximation. We argue that temperature dramatically influence the collinear and spiral magnetic phases, phase separation in the vicinity of half-filling. The results imply a possible interpretation of unusual behavior of magnetic properties of single-layer cuprates.