Order, criticality and excitations in the extended Falicov-Kimball model

Abstract

Using exact numerical techniques we investigate the nature of excitonic (electron-hole) bound states and the development of exciton coherence in the one-dimensional half-filled extended Falicov-Kimball model. The ground-state phase diagram of the model exhibits, besides band insulator and staggered orbital ordered phases, an excitonic insulator (EI) with power-law correlations. The criticality of the EI state shows up in the von Neumann entropy. The anomalous spectral function and condensation amplitude provide the binding energy and coherence length of the electron-hole pairs which, on their part, point towards a Coulomb interaction driven crossover from BCS-like electron-hole pairing fluctuations to tightly bound excitons. We show that while a mass imbalance between electrons and holes does not affect the location of the BCS-BEC crossover regime it favors staggered orbital ordering to the disadvantage of the EI. Within the BEC regime the quasiparticle dispersion develops a flat valence-band top in accord with the experimental finding for Ta${}_2$NiSe${}_5$.

5 pages, 4 figures, final version

References in corpus (7)

• Evidence for an excitonic insulator phase in 1T-TiSe${}_2$
• Room-Temperature Superfluidity in Graphene Bilayers
• On the possibility of an excitonic insulator at the semiconductor-semimetal transition
• Weak-coupling Treatment of Electronic (Anti-)Ferroelectricity in the Extended Falicov-Kimball Model
• Hartree-Fock study of electronic ferroelectricity in the Falicov-Kimball model with $f$-$f$ hopping
• Exact-diagonalization study of exciton condensation in electron bilayers
• Slave boson theory of the extended Falicov-Kimball model

Cited by in corpus (34)

• Cavity QED of Strongly Correlated Electron Systems: A No-go Theorem for Photon Condensation
• Nature of symmetry breaking at the excitonic insulator transition: Ta${}_2$NiSe${}_5$
• Excitonic condensation in systems of strongly correlated electrons
• Strong Coupling Nature of the Excitonic Insulator State in Ta${}_2$NiSe${}_5$
• Non-Coulomb strong electron-hole binding in $T{a}_{2}NiS{e}_5$ revealed by time- and angle-resolved photoemission spectroscopy
• Inhibition of the photoinduced structural phase transition in the excitonic insulator Ta${}_2$NiSe${}_5$
• Exciton-phonon cooperative mechanism of the triple-$q$ charge-density-wave and antiferroelectric electron polarization in TiSe${}_2$
• Fate of the excitonic insulator in the presence of phonons
• Orthorhombic-to-monoclinic transition in Ta${}_2$NiSe${}_5$ due to a zone-center optical phonon instability
• Roles of Hund's rule coupling in excitonic density-wave states
• Competition between excitonic charge and spin density waves: Influence of electron-phonon and Hund's rule couplings
• A New Era of Excitonic Insulators
• Nonequilibrium dynamics in the pump-probe spectroscopy of excitonic insulators
• Disentangling lattice and electronic instabilities in the excitonic insulator candidate Ta${}_2$NiSe${}_5$ by nonequilibrium spectroscopy
• Density waves in strongly correlated quantum chains
• Electric and magnetic multipoles and bond orders in excitonic insulators
• Photoinduced electron-electron pairing in the extended Falicov-Kimball model
• BCS-BEC crossover in a $(t_{2g}{)}^4$ Excitonic Magnet
• Formation and condensation of excitonic bound states in the generalized Falicov-Kimball model
• Excitonic Insulator State of the Extended Falicov-Kimball Model in the Cluster Dynamical Impurity Approximation
• Photoinduced metallization of excitonic insulators
• Effects of Disorder on the Transport of Collective Modes in an Excitonic Condensate
• Finite-temperature photoemission in the extended Falicov-Kimball model: a case study for Ta${}_2$NiSe${}_5$
• Third-harmonic generation in excitonic insulators
• Finite-temperature properties of excitonic condensation in the extended Falicov-Kimball model: Cluster mean-field-theory approach
• Spin texture and spin current in excitonic phases of the two-band Hubbard model
• The influence of nonlocal interactions on valence transitions and formation of excitonic bound states in the generalized Falicov-Kimball model
• Novel Block Excitonic Condensate at $n=3.5$ in a Spin-Orbit Coupled $t_{2g}$ Multiorbital Hubbard Model
• DMRG study of exciton condensation in the extended Falicov-Kimball model
• Excitonic Correlations, Spin-State Ordering, and Magnetic-Field Effects in One-Dimensional Two-Orbital Hubbard Model for Spin-Crossover Region
• Theory of Thermal Conductivity on Excitonic Insulator
• Combined effects of local and nonlocal hybridization on formation and condensation of excitons in the extended Falicov-Kimball model
• Effects of correlated hopping on electronic ferroelectricity in the extended Falicov-Kimball model in two dimensions
• BCS-BEC crossover of polaritonic condensates in mass-imbalanced semimetal/semiconductor microcavities