title: Ferroelectricity due to orbital ordering in E-type undoped rare-earth manganites.
abstract: Aiming at understanding the origin of the electronic contribution to ferroelectric polarization in undoped manganites, we evaluate the Berry phase of orbital-polarizable Bloch electrons as an orbital ordering (OO) establishes in the background of an antiferromagnetic E-type configuration. The onset of OO is tuned by the Jahn-Teller (JT) interaction in a tight-binding model for interacting electrons moving along zigzag chains. A finite polarization is found as soon as the JT coupling is strong enough to induce OO, supporting the large electronic contribution predicted from first principles.
authors.affiliation: CNR-SPIN, L'Aquila, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Barone
authors.forename: Kunihiko
authors.initials: K
authors.lastname: Yamauchi
authors.forename: Silvia
authors.initials: S
authors.lastname: Picozzi