Formation and condensation of excitonic bound states in the generalized Falicov-Kimball model

Abstract

The density-matrix-renormalization-group (DMRG) method and the Hartree-Fock (HF) approximation with the charge-density-wave (CDW) instability are used to study a formation and condensation of excitonic bound states in the generalized Falicov-Kimball model. In particular, we examine effects of various factors, like the $f$-electron hopping, the local and nonlocal hybridization, as well as the increasing dimension of the system on the excitonic momentum distribution $N(q)$ and especially on the number of zero momentum excitons $N_0=N(q=0)$ in the condensate. It is found that the negative values of the $f$-electron hopping integrals $t_f$ support the formation of zero-momentum condensate, while the positive values of $t_f$ have the fully opposite effect. The opposite effects on the formation of condensate exhibit also the local and nonlocal hybridization. The first one strongly supports the formation of condensate, while the second one destroys it completely. Moreover, it was shown that the zero-momentum condensate remains robust with increasing dimension of the system.

15 pages, 4 figures

References in corpus (3)

• Impact of Electron-Hole Correlations on the 1T-TiSe2 Electronic Structure
• Hartree-Fock study of electronic ferroelectricity in the Falicov-Kimball model with $f$-$f$ hopping
• Charge-density wave induced by combined electron-electron and electron-phonon interactions in 1$T$-TiSe${}_2$: A variational Monte Carlo study

Cited by in corpus (6)

• A New Era of Excitonic Insulators
• The influence of nonlocal interactions on valence transitions and formation of excitonic bound states in the generalized Falicov-Kimball model
• DMRG study of exciton condensation in the extended Falicov-Kimball model
• Topological spin-up triplet excitonic condensation in two-dimensional electron-hole systems
• Quantum coherent states of mass-imbalanced electron-hole system within optical microcavities
• Interplay of Rashba spin-orbit coupling and Coulomb interaction in topological spin-triplet excitonic condensates