Exciton condensation in an extended spinless Falicov Kimball model in the presence of orbital magnetic fields

TL;DR

This study investigates how perpendicular magnetic fields influence exciton condensation in an extended spinless Falicov-Kimball model, revealing suppression of excitonic average and strong flux-dependent effects.

Contribution

It introduces a detailed analysis of magnetic flux effects on exciton condensation within an extended Falicov-Kimball model using Hartree-Fock theory, highlighting flux-dependent behaviors.

Findings

Magnetic field suppresses excitonic average.

Coulomb interaction enhances exciton condensation.

f-electron hopping reduces exciton formation.

Abstract

An extended, spinless Falicov-Kimball model in the presence of perpendicular magnetic field is investigated employing Hartree-Fock self-consistent mean-field theory in two dimensions. In the presence of an orbital field the hybridization-dependence of the excitonic average ${ \Delta =<{{d_i}^\dagger} {f_i}>}$ is modified. The exciton responses in subtle different ways for different chosen values of the magnetic flux consistent with Hofstadter's well-known spectrum. The excitonic average is suppressed by the application of magnetic field. We further examine the effect of Coulomb interaction and $f$-electron hopping on the condensation of exciton for some rational values of the applied magnetic field. The interband Coulomb interaction enhances the $\Delta$ exponentially, while a non-zero $f$-electron hopping reduces it. A strong commensurability effect of the magnetic flux on the behaviour of the excitons is observed.