Electronic polarons in an extended Falicov-Kimball model

TL;DR

This paper investigates how hybridization and Coulomb interactions in a one-dimensional Falicov-Kimball model lead to a crossover from metallic to phase-separated states, highlighting the formation of an electronic polaron liquid and a Griffiths-like phase.

Contribution

It introduces the concept of an electronic polaron liquid and characterizes an intermediate-coupling Griffiths-like phase in an extended Falicov-Kimball model.

Findings

Crossover from mixed-valence metal to phase-separated state

Formation of an electronic polaron liquid

Identification of a Griffiths-like phase in the phase diagram

Abstract

We examine the one-dimensional spinless Falicov-Kimball model extended by a hybridization potential between the localized and itinerant electron states. Below half-filling we find a crossover from a mixed-valence metal to an integer-valence phase separated state with increasing on-site Coulomb repulsion. This crossover regime is characterized by local competition between the strong- and weak-coupling behaviour, manifested by the formation of an electronic polaron liquid. We identify this intermediate-coupling regime as a charge-analogy of the Griffiths phase; a phase diagram is presented and discussed in detail.