title: Charge order in LuFe2O4: antiferroelectric ground state and coupling to magnetism.
abstract: X-ray scattering by multiferroic LuFe2O4 is reported. Below 320 K, superstructure reflections indicate an incommensurate charge order with propagation close to (1/3 1/3 3/2). The corresponding charge configuration, also found by electronic structure calculations as most stable, contains polar Fe/O double layers with antiferroelectric stacking. Diffuse scattering at 360 K, with (1/3 1/3 0) propagation, indicates ferroelectric short-range correlations between neighboring double layers. The temperature dependence of the incommensuration indicates that charge order and magnetism are coupled.
authors.affiliation: Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA. m.angst@fz-juelich.de
authors.forename: M
authors.initials: M
authors.lastname: Angst
authors.forename: R P
authors.initials: RP
authors.lastname: Hermann
authors.forename: A D
authors.initials: AD
authors.lastname: Christianson
authors.forename: M D
authors.initials: MD
authors.lastname: Lumsden
authors.forename: C
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authors.lastname: Lee
authors.forename: M-H
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authors.lastname: Whangbo
authors.forename: J-W
authors.initials: JW
authors.lastname: Kim
authors.forename: P J
authors.initials: PJ
authors.lastname: Ryan
authors.forename: S E
authors.initials: SE
authors.lastname: Nagler
authors.forename: W
authors.initials: W
authors.lastname: Tian
authors.forename: R
authors.initials: R
authors.lastname: Jin
authors.forename: B C
authors.initials: BC
authors.lastname: Sales
authors.forename: D
authors.initials: D
authors.lastname: Mandrus