DOI:10.5488/CMP.18.33704 arXiv:1510.06562
Title:
Effects of correlated hopping on electronic ferroelectricity
in the extended Falicov-Kimball model in two dimensions
Author(s):
| P. Farkašovský (Institute of Experimental Physics, Slovak Academy of Sciences Watsonova 47, 040 01 Košice, Slovakia) , | |
| J. Jurečková (Institute of Experimental Physics, Slovak Academy of Sciences Watsonova 47, 040 01 Košice, Slovakia) , |
We use the Hartree-Fock (HF) approximation with the charge-density-wave (CDW) instability to study the influence of correlated hopping on the stability of electronic ferroelectricity in the extended Falicov-Kimball model (FKM) in two dimensions. It is shown that effects of the correlated hopping term are very strong, especially for negative values of the f-level energy Ef, where they lead to: (i) the stabilization of the ferroelectric ground state with a spontaneous hybridization Pdf=< d^+f > for positive values of correlated hopping parameter t'd, (ii) the stabilization of the antiferroelectric phase for t'd < t'd,crit. < 0 and (iii) the suppression of the ferroelectric ground state for t'd,crit. ≤ t'd < 0, The effects of the correlated hopping on valence transitions are also discussed.
Key words:
electronic ferroelectricity, charge density waves, valence transitions
PACS:
71.27.+a, 71.28.+d, 71.30.+h
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