Superconducting, ferromagnetic and antiferromagnetic phases in the t-t' Hubbard model

TL;DR

This paper uses a renormalization group method to explore the phase diagram of the t-t' Hubbard model at Van Hove filling, revealing competing ferromagnetic, antiferromagnetic, and d-wave superconducting phases.

Contribution

It provides a detailed phase diagram analysis of the t-t' Hubbard model at small U/t, highlighting the interplay of different magnetic and superconducting phases.

Findings

Identification of ferromagnetic, antiferromagnetic, and d-wave superconducting phases.

Antiferromagnetism and superconductivity originate from the same interactions.

Competition between phases depends on the t'/t ratio.

Abstract

We apply a renormalization group approach to the determination of the phase diagram of the t-t' Hubbard model at the Van Hove filling, as function of t'/t, for small values of U/t. The model presents ferromagnetic, antiferromagnetic and d-wave superconducting phases. Antiferromagnetism and d-wave superconductivity arise from the same interactions, and compete in the same region of parameter space.