Mott transitions with partially-filled correlated orbitals

TL;DR

This paper explores the conditions and nature of the Mott metal-insulator transition in a generalized periodic Anderson model with hybridized bands, revealing the importance of total filling and the transition's first-order character.

Contribution

It introduces a detailed analysis of the Mott transition in a hybridized band system, emphasizing the role of total filling and the transition's first-order nature.

Findings

Mott transition occurs at integer total filling of the two bands.

System remains metallic at large interactions if the correlated band has constant occupation.

Transition involves localization of singlet states between itinerant and correlated electrons.

Abstract

We investigate the metal-insulator Mott transition in a generalized version of the periodic Anderson model, in which a band of itinerant electrons is hybridrized with a narrow and strongly correlated band. Using dynamical mean-field theory, we show that the precondition for a Mott transition is an integer total filling of the two bands, while for an integer constant occupation of the correlated band the system remains a correlated metal at arbitrary large interaction strength. We picture the transition at a non-integer filling of the correlated orbital as the Mott localization of the singlet states between itinerant and strongly interacting electrons, having occupation of one per lattice site. We show that the Mott transition is of the first-order and we characterize the nature of the resulting insulating state with respect to relevant physical parameters, such as the charge-transfer energy.