Magnetic properties of the three-band Hubbard model

TL;DR

This paper investigates the magnetic properties of the three-band Hubbard model using DMFT, revealing complex spectral features and phase stability asymmetries that align with experimental observations in high-T_c superconductors.

Contribution

The study extends DMFT to AB-like lattices with broken spin symmetry, providing new insights into spectral functions and phase diagrams of the three-band Hubbard model.

Findings

Rich spectral structures above critical magnetization similar to the t-J model

Enhanced antiferromagnetic stability in electron-doped systems

Qualitative agreement with high-T_c experimental phase diagrams

Abstract

We present magnetic properties of the three-band Hubbard model in the para- and antiferromagnetic phase on a hypercubic lattice calculated with the Dynamical Mean-Field Theory (DMFT). To allow for solutions with broken spin-symmetry we extended the approach to lattices with AB-like structure. Above a critical sublattice magnetization m_d=0.5 one can observe rich structures in the spectral-functions similar to the t-J model which can be related to the well known bound states for one hole in the Neel-background. In addition to the one-particle properties we discuss the static spin-susceptiblity in the paramagnetic state at the points q=0 and q=(pi,pi,pi,...) for different dopings delta. The delta-T-phase-diagram exhibits an enhanced stability of the antiferromagnetic state for electron-doped systems in comparison to hole-doped. This asymmetry in the phase diagram is in qualitative agreement with experiments for high-T_c materials.