Non-local correlations in the orbital selective Mott phase of a one dimensional multi-orbital Hubbard model

TL;DR

This study investigates non-local correlations in a one-dimensional multi-orbital Hubbard model, revealing momentum-dependent self-energies in the orbital selective Mott phase and the evolution of orbital and magnetic orderings with temperature.

Contribution

It provides new insights into non-local correlations and momentum-dependent self-energies in the orbital selective Mott phase of a 1D multi-orbital Hubbard model, using advanced numerical methods.

Findings

Orbital ordering precedes magnetic correlations with decreasing temperature.

Self-energy for itinerant electrons shows momentum dependence in the OSMP.

Non-local correlations cause shifts in electron and hole bands.

Abstract

We study non-local correlations in a three-orbital Hubbard model defined on an extended one-dimensional chain using determinant quantum Monte Carlo and density matrix renormalization group methods. We focus on a parameter with robust Hund's coupling, which produces an orbital selective Mott phase (OSMP) at intermediate values of the Hubbard U, as well as an orbitally ordered ferromagnetic insulating state at stronger coupling. An examination of the orbital and spin-correlation functions indicates that the orbital ordering occurs before the onset of magnetic correlations in this parameter regime as a function of temperature. In the OSMP, we find that the self-energy for the itinerant electrons is momentum dependent, indicating a degree of non-local correlations while the localized electrons have largely momentum independent self-energies. These non-local correlations also produce relative shifts of the hole-like and electron-like bands within our model. The overall momentum dependence of these quantities is strongly suppressed in the orbitally-ordered insulating phase.