Combined effects of local and nonlocal hybridization on formation and condensation of excitons in the extended Falicov-Kimball model

Abstract

We study the combined effects of local and nonlocal hybridization on the formation and condensation of the excitonic bound states in the extended Falicov-Kimball model by the density-matrix-renormalization-group (DMRG) method. Analysing the resultant behaviours of the excitonic momentum distribution $N(q)$ we found, that unlike the local hybridization $V$, which supports the formation of the $q=0$ momentum condensate, the nonlocal hybridization $V_n$ supports the formation of the $q=\pi$ momentum condensate. The combined effect of local and nonlocal hybridization further enhances the excitonic correlations in $q=0$ as well as $q=\pi$ state, especially for $V$ and $V_n$ values from the charge-density-wave (CDW) region. Strong effects of local and nonlocal hybridization are observed also for other ground-state quantities of the model such as the $f$-electron density, or the density of unbound $d$-electrons, which are generally enhanced with increasing $V$ and $V_n$. The same calculations performed for nonzero values of $f$-level energy $E_f$ revealed that this model can yield a reasonable explanation for the pressure-induced resistivity anomaly observed experimentally in $TmS{e}_{0.45}T{e}_{0.55}$ compound.

14 pages, 5 figures

References in corpus (4)

• Models of coherent exciton condensation
• Impact of Electron-Hole Correlations on the 1T-TiSe2 Electronic Structure
• Order, criticality and excitations in the extended Falicov-Kimball model
• Formation and condensation of excitonic bound states in the generalized Falicov-Kimball model

Cited by in corpus (2)

• 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