Effect of Hund's exchange on the spectral function of a triply orbital degenerate correlated metal

TL;DR

This paper investigates how Hund's exchange interaction influences the spectral properties of a triply degenerate Hubbard model near the metal-insulator transition using dynamical mean field theory.

Contribution

It introduces a DMFT-based approach with a generalized non-crossing approximation to analyze Hund's exchange effects in a triply degenerate correlated metal.

Findings

Hund's coupling significantly affects low energy dynamics.

Band-filling critically influences Hund's exchange impact.

Method effectively maps lattice to local Anderson model.

Abstract

We present an approach based on the dynamical mean field theory which is able to give the excitation spectrum of a triply degenerate Hubbard model with a Hund's exchange invariant under spin rotation. The lattice problem can be mapped onto a local Anderson model containing 64 local eigenstates. This local problem is solved by a generalized non-crossing approximation. The influence of Hund's coupling J is examined in detail for metallic states close to the metal insulator transition. The band-filling is shown to play a crucial role concerning the effect of J on the low energy dynamics.