Two-particle photoemission from strongly correlated systems: A dynamical-mean field approach

TL;DR

This paper investigates two-particle photoemission in strongly correlated systems using the Hubbard model, employing multiple theoretical methods to analyze the spectral function near metal-insulator transitions and the effects of doping and orbital degeneracy.

Contribution

It introduces a comprehensive theoretical framework combining DMFT, QMC, perturbation, and ladder approximations to study two-particle excitations in correlated materials.

Findings

Spectral functions vary with correlation strength and doping.

Orbital degeneracy influences interband correlations.

Results provide insights for experimental realization.

Abstract

We study theoretically the simultaneous, photo-induced two-particle excitations of strongly correlated systems on the basis of the Hubbard model. Under certain conditions specified in this work, the corre- sponding transition probability is related to the two-particle spectral function which we calculate using three different methods: the dynamical-mean field theory combined with quantum Monte Carlo (DMFT- QMC) technique, the first order perturbation theory and the ladder approximations. The results are analyzed and compared for systems at the verge of the metal-insulator transitions. The dependencies on the electronic correlation strength and on doping are explored. In addition, the account for the orbital degeneracy allows an insight into the influence of interband correlations on the two particle excitations. A suitable experimental realization is discussed.