Eliminating Orbital Selectivity from the Metal-Insulator Transition by Strong Magnetic Fluctuations

TL;DR

This paper demonstrates that strong magnetic fluctuations in a multi-orbital Hubbard model suppress the orbital-selective Mott transition, leading to a unified magnetic transition across orbitals, challenging local correlation theories.

Contribution

It reveals that spatial magnetic fluctuations can eliminate orbital selectivity in the metal-insulator transition, extending beyond local theoretical approaches.

Findings

Magnetic fluctuations prevent orbital-selective Mott transition.

Both orbitals undergo Neel transition simultaneously.

Spatial collective fluctuations dominate over local correlations.

Abstract

The orbital-selective electronic behavior is one of the most remarkable manifestations of strong electronic correlations in multi-orbital systems. A prominent example is the orbital-selective Mott transition (OSMT), which is characterized by the coexistence of localized electrons in some orbitals, and itinerant electrons in other orbitals. The state-of-the-art theoretical description of the OSMT in two- and three-dimensional systems is based on local non-perturbative approximations to electronic correlations provided by dynamical mean-field theory or slave spin method. In this work we go beyond this local picture and focus on the effect of spatial collective electronic fluctuations on the OSMT. To this aim, we consider a half-filled Hubbard-Kanamori model on a cubic lattice with two orbitals that have different bandwidths. We show that strong magnetic fluctuations that are inherent in this system prevent the OSMT and favor the N\'eel transition that occurs at the same critical temperature for both orbitals.