Eur. Phys. J. B 64, 43-50 (2008)
https://doi.org/10.1140/epjb/e2008-00273-y

Weak-coupling treatment of electronic (anti-)ferroelectricity in the extended Falicov-Kimball model

Institute for Theoretical Physics, University of Bremen, 28334 Bremen, Germany

Corresponding author: ^a czycholl@itp.uni-bremen.de

Received: 13 February 2008
Revised: 12 June 2008
Published online: 16 July 2008

Abstract

We study the (spinless) Falicov-Kimball model extended by a finite band width (hopping t_f) of the localized (f-) electrons in infinite dimensions in the weak-coupling limit of a small local interband Coulomb correlation U for half filling. In the case of overlapping conduction- and f-bands different kinds of ordered solutions are possible, namely charge-density wave (CDW) order, electronic ferroelectricity (EFE) and electronic antiferroelectricity (EAFE). The order parameters are calculated as a function of the model parameters and of the temperature. There is a first-order phase transition from the CDW-phase to the EFE- or EAFE-phase. The total energy is calculated to determine the thermodynamically stable solution. The quantum phase diagrams are calculated.