title: Dielectric anomalies in ferroelectric nanostructures.
abstract: First-principles-based methods are used to determine the external dielectric susceptibility (i.e., the polarization response to the external electric field) and the internal susceptibility (i.e., the polarization response to the average internal field) in ferroelectric dots, wires, and films, as a function of the electrical boundary conditions. While the external susceptibility is obviously positive, we find that the internal one is negative over a wide range of boundary conditions for all kinds of nanostructures. A Landau-type phenomenological model provides a rationale for all of our findings.
authors.affiliation: Department of Physics, University of Arkansas, Fayetteville, Arkansas 72701, USA. iponoma@uark.edu
authors.forename: I
authors.initials: I
authors.lastname: Ponomareva
authors.forename: L
authors.initials: L
authors.lastname: Bellaiche
authors.forename: R
authors.initials: R
authors.lastname: Resta