Temperature-dependent electronic structure and ferromagnetism in the d=oo Hubbard model studied by a modfied perturbation theory

TL;DR

This paper investigates the temperature-dependent electronic structure and ferromagnetism in the infinite-dimensional Hubbard model using a modified perturbation theory, providing insights into magnetic properties across different fillings and lattice types.

Contribution

It introduces a modified perturbation approach that is exact in the atomic limit and accurately captures Hubbard band dispersions for arbitrary fillings.

Findings

Ferromagnetic solutions found for fcc-type lattice.

Curie temperature depends on filling and matches Quantum Monte Carlo results.

Method accurately describes strong and weak coupling regimes.

Abstract

The infinite-dimensional Hubbard model is studied by means of a modified perturbation theory. The approach reduces to the iterative perturbation theory for weak coupling. It is exact in the atomic limit and correctly reproduces the dispersions and the weights of the Hubbard bands in the strong-coupling regime for arbitrary fillings. Results are presented for the hyper-cubic and an fcc-type lattice. For the latter we find ferromagnetic solutions. The filling-dependent Curie temperature is compared with the results of a recent Quantum Monte Carlo study.