Spectral functions of the Falicov-Kimball model with electronic ferroelectricity

TL;DR

This paper investigates the spectral properties of the Falicov-Kimball model with electronic ferroelectricity, revealing how exciton interactions influence electronic structures and quasiparticle behavior in two dimensions.

Contribution

It provides the first detailed calculation of the angular resolved photoemission spectrum for this model, highlighting the formation of pseudospin polarons and flat band regions.

Findings

Presence of pseudospin polarons in mix-valence regimes

Flat regions near the bottom of the quasiparticle band in 2D

Bandwidth scaling with $d$-$f$ excitons

Abstract

We calculate the angular resolved photoemission spectrum of the Falicov-Kimball model with electronic ferroelectricity where $d$- and $f$-electrons have different hoppings. In mix-valence regimes, the presence of strong scattering processes between $d$-$f$ excitons and a hole, created by emission of an electron, leads to the formation of pseudospin polarons and novel electronic structures with bandwidth scaling with that of $d$-$f$ excitons. Especially, in the two-dimensional case, we find that flat regions exist near the bottom of the quasiparticle band in a wide range of the $d$- and $f$-level energy difference.