title: Intermediate coupling theory of electronic ferroelectricity.
abstract: We calculate the quantum phase diagram of an extended Falicov-Kimball model for one- and two-dimensional systems in the intermediate coupling regime. Even though some features of the phase diagram are obtained analytically, the main results are calculated with a constrained path Monte Carlo technique. We find that this regime is dominated by a Bose-Einstein condensation of excitons with a built-in electric polarization. The inclusion of a finite hybridization between the bands removes the condensate but reinforces the ferroelectricity.
authors.affiliation: Center for Nonlinear Studies and Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
authors.forename: C D
authors.initials: CD
authors.lastname: Batista
authors.forename: J E
authors.initials: JE
authors.lastname: Gubernatis
authors.forename: J
authors.initials: J
authors.lastname: Bonca
authors.forename: H Q
authors.initials: HQ
authors.lastname: Lin