Ground-state phase diagrams of the generalized Falicov-Kimball model with Hund coupling

TL;DR

This paper investigates the ground-state phase diagrams of a generalized Falicov-Kimball model with Hund coupling in 1D and 2D lattices, revealing rules for phase formation and the influence of doping on charge and magnetic structures.

Contribution

It introduces a set of simple rules for the formation of ground state phases in the model, including relationships between carrier density and charge/magnetic arrangements.

Findings

Axial stripe phases in 2D with ferromagnetic or antiferromagnetic chains

Stripe phases near half-filling oriented along diagonals

Charge and magnetic modulations can be tuned by doping

Abstract

Charge and spin orderings are studied on the simplest 1D and the 2D square lattice within the generalized Falicov-Kimball model with Hund coupling between localized and itinerant electrons. Using the restricted phase diagrams method (RPDM) a number of simple rules of formation of various sorts of ground state phases have been detected. In particular, relationships between density of current carriers (electrons or holes) and type of charge and magnetic arrangement has been determined. In 2D in the mixed valence regime only axial stripes (vertical or horizontal) have been found for intermediate values of the coupling constants. They are composed of ferromagnetic or antiferromagnetic chains interchanged with non-magnetic ones. For band fillings close to the half filling stripe phases oriented along one of the main diagonal direction are formed. The results suggest a possibility of tuning modulations of charge and magnetic superstructures with a change of doping.