Slave boson theory of the extended Falicov-Kimball model

Abstract

The extended Falicov-Kimball model, with both an on-site hybridization potential and dispersive narrow band, is examined within the saddle-point approximation to the Kotliar-Ruckenstein slave boson theory. We first set the hybridization potential to zero and find that the phase diagram depends strongly upon the orbital structure: for degenerate orbitals, a correlated-insulating state is found at sufficiently strong interaction strengths, whereas a finite orbital energy difference can lead to discontinuous valence transitions. The obtained phase diagram is very sensitive to the presence of a finite hybridization potential. As in Hartree-Fock theory, we find an enhancement of the hybridization by the inter-orbital Coulomb repulsion. The more precise treatment of correlation effects, however, leads to large deviations from the Hartree-Fock results. In the limit of vanishing hybridization an excitonic insulator state is only found when the orbitals are degenerate, which restricts this phase to a much smaller parameter space than in other available mean-field theories.

arXiv comment23 pages, 10 figures

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Cited by in corpus (14)

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• Bound state formation and nature of the excitonic insulator phase in the extended Falicov-Kimball model
• On the existence of the excitonic insulator phase in the extended Falicov-Kimball model: an SO(2)-invariant slave-boson approach
• Order, criticality and excitations in the extended Falicov-Kimball model
• Weak-coupling Treatment of Electronic (Anti-)Ferroelectricity in the Extended Falicov-Kimball Model
• Spectral properties of orbital polarons in Mott insulators
• Excitonic resonances in the 2D extended Falicov-Kimball model
• Slave-boson field fluctuation approach to the extended Falicov-Kimball model: charge, orbital, and excitonic susceptibilities
• Exciton condensation due to electron-phonon interaction
• Electric and magnetic multipoles and bond orders in excitonic insulators
• Phase diagram of the asymmetric Hubbard model and an entropic chromatographic method for cooling cold fermions in optical lattices
• Competing chiral and multipolar electric phases in the extended Falicov-Kimball model
• Finite-temperature photoemission in the extended Falicov-Kimball model: a case study for Ta${}_2$NiSe${}_5$
• Magnetic-field effect on excitonic condensation emergent in extended Falicov-Kimball model