Competing chiral and multipolar electric phases in the extended Falicov-Kimball model

TL;DR

This paper investigates how interband hybridization influences the competition between chiral and multipolar electric phases in an extended Falicov-Kimball model, revealing symmetry breaking effects and phase diagram structures.

Contribution

It provides a detailed analysis of the effects of interband hybridization on phase degeneracy and phase diagrams in the extended Falicov-Kimball model.

Findings

Interband hybridization breaks U(1) symmetry.

Degeneracy between phases is lifted.

Phase diagrams differ in weak and strong coupling.

Abstract

We study the effects of interband hybridization within the framework of an extended Falicov-Kimball model with itinerant $c$ and $f$ electrons. An explicit interband hybridization breaks the U(1) symmetry associated with the conservation of the difference between the total number of particles in each band. As a result, the degeneracy between multipolar electric and chiral orderings is lifted. We analyze the weak- and strong-coupling limits of the $c$-$f$ electron Coulomb interaction at zero temperature, and derive the corresponding mean-field quantum phase diagrams at half-filling for a model defined on a square lattice.