Effects of correlated hopping on electronic ferroelectricity in the extended Falicov-Kimball model in two dimensions

Abstract

We use the Hartree-Fock (HF) approximation with the charge-density-wave (CDW) instability to study the effect of correlated hopping on the stability of electronic ferroelectricity in the extended Falicov-Kimball model (FKM) in two dimensions. It is shown that the effects of correlated hopping term are very strong, especially for negative values of the $f$-level energy $E_f$, where they lead to: (i) stabilization of the ferroelectric ground state with a spontaneous hybridization $P_{df}=⟨d^{+}f⟩$ for positive values of correlated hopping parameter $t_d^{\prime }$, (ii) stabilization of the antiferroelectric phase for $t_d^{\prime }<t_{d,crit.}^{\prime }<0$ and (iii) suppression of the ferroelectric ground state for $t_{d,crit.}^{\prime }⩽t_d^{\prime }<0$, The effects of correlated hopping on valence transitions are also discussed.

8 pages, 5 figures

References in corpus (3)

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